C.3 OCCUPATIONAL HEALTH AND SAFETY

The purpose of this section is to describe the program to ensure safe working conditions at LLNL and SNL, Livermore. Workers at LLNL and SNL, Livermore can be potentially exposed to radioactive materials, radiation from sources and devices, hazardous industrial chemicals, and to a variety of other industrial hazards, such as lasers, noise, high explosives, nonionizing radiation, electricity, and general construction activities.

It is the policy of DOE and UC (1) to assure the protection of the environment and the health and safety of the public, and (2) to assure safe and healthful work place conditions of employment for all employees of DOE and DOE contractors. Shortly after taking office as the U.S. Secretary of Energy, Admiral James D. Watkins set forth his policy for placing added emphasis on environmental protection, safety, and health within the Department of Energy: "I am placing into effect immediately a resetting of priorities to reflect environment, safety, and health as more heavily weighted than production" (LLNL, 1991e).

All management levels of LLNL and SNL, Livermore are responsible for developing and implementing procedures to protect workers against hazards in the workplace. At LLNL these procedures include Facility Safety Procedures, which are required by the facility managers and Operational Safety Procedures, which are required by the program managers. The Facility Safety Procedures and Operational Safety Procedures are discussed in greater detail in section C.5.2.1. At SNL, Livermore, supervisors are required to assess the hazards associated with their operations using a Preliminary Hazards Assessment. A Safe Operating Procedure must be prepared for all operations that could expose workers to unsafe working conditions or hazards. These procedures are discussed more fully in section C.3.2.2. Workers at the Laboratories are responsible for adhering to these safe working procedures, and line managers are responsible for ensuring compliance by the workers under their supervision. LLNL and SNL, Livermore each have organizations responsible for providing guidance and advice on worker and environmental protection and for monitoring worker safety. These organizations also prepare the reports required for submission to DOE and to other environmental protection agencies.

C.3.1 LLNL

C.3.1.1 Radiation Exposures

Workers at LLNL may be exposed either internally or externally to radiation. Internal exposures arise when radioactive materials are deposited in the body through inhalation, ingestion, or absorption through intact skin or open wounds in the skin. The absorbed radiation dose resulting from an internal exposure is determined from the results of the bioassay (urinalysis, whole-body counting, and fecal analysis) program (LLNL, 1989a). Internal exposures are minimized through the use of administrative controls, engineering devices (such as high volume air hoods), and personal protective equipment (such as gloves, protective clothing, and respirators).

At LLNL, internal radiation exposures occur periodically in the Hydrogen Research Facility (Building 331). The work areas are monitored continuously for tritium in the room air and periodically for tritium contamination on accessible surfaces. If the tritium concentration in the room air exceeds guidelines established by the Hazards Control Department, the work areas are evacuated until the concentration is reduced to an acceptable level. If the accessible surfaces are found to be contaminated above levels established for them, the workers are required to decontaminate their work areas before proceeding with their work. All workers in the building have routine bioassays (urinalysis) on a weekly basis to monitor intakes of tritium. During 1990, the maximum effective dose equivalent to any individual was 0.16 rem, compared to the dose limit of 5 rem (Mansfield, 1991; DOE, 1988c). The summation of the internal radiation doses to all workers in the building during 1990, or the collective internal dose, was 0.5 person-rem of effective dose equivalent (Mansfield, 1991). Most of the collective dose was distributed among six individuals. Figure C-4 shows the maximum individual and total collective occupational effective dose equivalents due to tritium exposures at Building 331 for 1986 through 1990.

Workers handling radionuclides other than tritium seldom have measurable internal depositions of radionuclides. Nevertheless, routine bioassay measurements (urinalysis and whole-body counting) are made for personnel working in a number of facilities, including Buildings 251 (Heavy Element Facility), 490 and 175 (Atomic Vapor Laser Isotope Separation Facilities) 332 (Plutonium Facility), and 612 (Waste Treatment and Storage). The personnel who are included in the routine bioassay program are selected on the basis of their work activities and the types of materials which are utilized. Room air monitors, routine worker monitoring, and periodic radiation surveys are used to monitor worker exposure conditions. If any of these monitoring systems indicate potential for internal exposure, additional bioassays are performed.

Bioassay measurements are also made when inadvertent events result in the potential for internal radiation exposures to workers. When results greater than reference levels are observed followup bioassay studies are conducted to confirm and assess the intakes of radionuclides (LLNL, 1989a). The follow-up studies may include urinanalysis, whole-body counting and fecal analysis.

External exposures are those received from radiation-emitting sources outside the body, such as accelerators, x-ray machines, or radioactive sources. All personnel at LLNL are assigned a thermoluminescent dosimeter that is attached to their security badge. The security badge and thermoluminescent dosimeter must be worn at all times during work on the site. The dosimeter measures the amount of external radiation dose the worker receives while working on the site. Work area monitors are used to monitor the radiation levels in the work place. Worker access would be restricted if the levels exceed those stated in the applicable regulatory guidelines. External exposures are minimized through the use of administrative controls (such as operating procedures, limiting the duration of exposures, and removing nonessential personnel from areas of potential exposure) and engineering controls (such as shielding, and installing lock-out mechanisms on doors to radiation-producing machines).

The total radiation dose for workers considers both internal and external exposure while working at LLNL. The exposure records for workers at LLNL in 1990 show that the majority of measurable radiation doses received by the workers were from external sources. During 1990, the total radiation doses received by LLNL personnel ranged from levels indistinguishable from background radiation levels to 1.47 rem. The highest radiation dose (1.47 rem) was entirely due to external radiation and represented 29 percent of the annual occupational dose limit of 5 rem (LLNL, 1991g; DOE, 1988c).

About two-thirds of the external radiation exposure to workers at LLNL occurs as a consequence of the operations at the Plutonium Facility (Building 332). Figure C-5 shows the maximum individual and the collective occupational exposures due to external radiation at the Plutonium Facility from 1986 through 1990.

The summation of all external radiation doses received by workers at LLNL during 1990 was 28 person-rem. The summation of all internal radiation doses received by workers at LLNL during 1990 which resulted from the intake of tritium was 0.5 person-rem. The average radiation dose for all workers was 0.003 rem for the year, or about 0.06 percent of the annual dose limit. The vast majority (97 percent) of workers at LLNL did not receive any measurable external radiation exposures above background radiation levels. Figure C-6 shows the distribution of total doses from external exposures for 1988, 989, and 1990. Figure C-7 shows the summation of annual doses to all workers in person-rem due to external exposures and tritium exposures at LLNL from 1971 through 1990 (LLNL, 1991g). A trend analysis indicates that the collective radiation dose decreased by an average of approximately 7.5 percent per year from 1971 through 1990.

The exposure records at LLNL also include internal doses being received from internal depositions of radionuclides which occurred in the past at facilities other than LLNL. Although these radionuclides continue to contribute to the workers' total radiation dose and are considered in their radiation exposure evaluations, they are not the result of operations at LLNL.

In addition to the routine exposures, inadvertent releases of radioactive materials may expose workers at LLNL to radiation. DOE Order 5000.3A requires reporting of unusual occurrences, and these reports were reviewed to determine the contribution of such incidents to the occupational radiation exposure at LLNL. The following are unusual occurrences, as defined by DOE Order 5000.3A, which resulted in occupational exposures since 1983:

• In May 1988, a microscope was disassembled for repair in Building 332. The technician did not know that the microscope was internally contaminated with plutonium. Minor surface contamination resulted and an estimated 0.5 nCi (500 pCi) of plutonium was taken up by the worker. The 50-year committed effective dose equivalent to the worker was estimated to be 0.1 rem.
• On April 2, 1991, a worker in Building 331 inhaled tritiated water vapor during an

unplanned release that occurred while he was preparing a helium-3 reservoir for pressure and content analysis. The valve on the container holding the tritium failed and an estimated 144 curies of tritium leaked into the work area. This worker received an effective dose equivalent of about 1.1 rem compared with the annual occupational dose limit for workers of 5 rem. Three other workers received doses of less than 0.02 rem during recovery efforts. The potential radiation dose at the fenceline was estimated, by the Environmental Monitoring Group of LLNL, to be less than 0.00001 rem.

In addition to these two events, since 1980, four other LLNL workers have had bioassays showing recordable intakes of radionuclides other than tritium, and these intakes also resulted from nonroutine events. The calculated 50-year committed effective dose equivalents to these four workers range from 0.17 to 2.03 rem (Mansfield, 1991). This information is presented in Table C-2

. These doses may be compared to DOE dose limit (for design and operation) of 5 rem (DOE, 1988c). The 50-year committed effective dose equivalent is the dose which is received over a 50-year period from the date of intake (see Glossary for more information).

C.3.1.2 Toxic Exposures and Physical Hazards

As described in Appendix A, Laboratory operations and research involve the use of a wide variety of chemicals and physical hazards that could result in short and/or long-term exposures. Workers may be exposed to a variety of toxic chemical and physical hazards at LLNL. Typical physical hazards include magnetic fields, lasers, electrical shock, falling, and noise as well as normal construction activities, skin abrasions, and muscle strains. The purpose of this section is to examine typical potential exposures, expected health effects associated with these exposures, and programs that are in place to limit and reduce potential exposures. The hazards that resulted in the greatest number of injuries or lost or restricted workdays in 1990 are also discussed in this section.

Industrial Hygiene

Some workers at LLNL are potentially exposed to toxic chemicals and physical hazards. LLNL is a research and development facility; therefore, ongoing processes with long-term exposure to chemicals occur on a daily basis. The small number of workers who may be exposed to toxic chemicals are exposed in small quantities and only sporadically.

The Hazards Control Department evaluates the workplace to ensure that potential exposures are as low as reasonably achievable, and LLNL has a program in place to ensure that the workers are protected from potential workplace hazards. This program is documented in the LLNL Health and Safety Manual (LLNL, 1990c).

Safety procedures are the foundation of worker safety at LLNL. These include the Facility Safety Procedures, basic safety ground rules that must be followed by all personnel present within a building or area, and the Operational Safety Procedures, used primarily by experimenters for specific operations. The Operational Safety Procedures are more limited in scope and more specific in content than the Facility Safety Procedures. These safety procedures are discussed in greater detail in section C.5.2.1.

Toxic Chemicals

The records of concentrations of all toxic materials that were measured (during routine inspections, by continuous room monitors, stack monitors, personnel samplers, etc.) by the Hazards Control Department in 1990 were reviewed. These measurements were compared to OSHA permissible exposure limits. However, they should not be considered an indication of exposure. The type of air sample, engineering controls, or personnel protective equipment would be considered in determining exposure. There were over 1250 measurements of ambient air concentrations of toxic materials in 1990. In 950 of the 1250 samples, the chemical that the sample was being analyzed for was not detected.

There were 9 instances where the measured concentration exceeds the Occupational Safety and Health Administration (OSHA) permissible exposure limits Time-Weighted Averages. The permissible exposure limits—time weighted average values are concentrations of airborne substances and represent conditions under which it is believed that nearly all workers may be repeatedly exposed day after day without adverse health effects (29 C.F.R. pt. 1910, 1989). The limit is based on a normal 8-hour work day and a 40-hour work week. The permissible exposure limits—time weighted average values and the measured concentrations are presented in Table C-3. These 1250 sample results evidence the effectiveness of the LLNL's program to maintain worker exposures below limits.

The LLNL Health and Safety Manual (LLNL, 1990d) details how toxic chemicals are to be handled by workers. Whenever a chemical is introduced into a laboratory or work area at LLNL, it is accompanied by a material safety data sheet (MSDS). Each data sheet provides detailed information on the physical, chemical, and physiological properties of a particular chemical and on recommended control procedures to be used during handling. Material safety data sheets are kept in files so that they are available to workers at LLNL. A Health Hazard Communication Program is also in place providing training for workers. Supervisors are responsible for identifying the necessary protective equipment and for instructing their personnel as to the possible hazards, safety precautions, waste handling procedures, actions to take in case of an accident, and consequences of an accident. Employees are required to learn and understand the properties of the toxic chemicals they work with and to follow all precautions applicable to each task. For example, practices associated with handling the dyes used as the lasing medium are delineated; they include control of the quantities of dye, the use of the vehicle with which the dye is mixed, and the cleanup and disposal of waste material (LLNL, 1990e). The Hazards Control Department assists supervisors and employees in maintaining safe work areas by providing information on the hazardous properties of materials, recommending methods for controlling them, and monitoring the work environment (LLNL, 1990d).

LLNL scientists are currently working to develop a personal chemical exposure monitor that will monitor the amount of chemicals to which each employee is exposed. This monitor is expected to provide a reliable chemical exposure record of the work environment in which it is worn. This monitor is still in development.

The Health Services Department provides an opportunity to all LLNL employees who work with hazardous chemicals to receive medical attention whenever an employee is concerned or develops signs or symptoms associated with a hazardous chemical to which the employee may have been exposed. In addition, the Health Services Department provides medical attention whenever an event takes place in the work area, such as a spill, leak, explosion, or other occurrence resulting in the likelihood of a hazardous exposure. After the examination and treatment, the Health Services Department provides a report to the employee's supervisor that discusses the results of the examination, recommendations for further medical follow-up, any work restrictions, and a statement verifying that the employee has been informed of the results of the consultation (LLNL, 1990f).

Carcinogens

At LLNL, chemical carcinogens are used by Laboratory employees only when required by the specific research project and no other practical substitutes can be found. When the use of chemical carcinogens is unavoidable, every effort is made to minimize employee exposure to levels as low as reasonably achievable and to limit the size of the work area. Any work involving the use of chemical carcinogens must follow specific procedures for: purchasing and receiving, posting and labeling, packaging and storage, inventory, and decontamination and disposal. Proper employee education, training, and medical surveillance are also a part of the general requirements for usage of chemical carcinogens.

The use, synthesis, and storage of carcinogens must be evaluated by an industrial hygienist. Depending on the nature of the chemical use, the quantity of material involved, and the control measures engaged, an Operational Safety Procedure may or may not be required. For certain highly potent carcinogens, the area industrial hygienist may request the user to maintain a log of the chemical and the quantity used.

The purchasing and receiving of chemical carcinogens is controlled by several factors. Laboratory guidelines restrict the purchase of these chemicals to only the amount of material necessary for the specific project. Some carcinogenic solvents such as benzene and chloroform, are available from internal LLNL Stores upon authorization from Materials Management. Authorization to use such chemicals requires the user to show an appropriate Operation Safety Procedure or obtain approval from the area industrial hygienist. Unless approved by an area industrial hygienist, carcinogens can not be ordered.

Handling and internal transfer of carcinogens are conducted with extreme care to avoid any accidental release or personnel exposure. In addition, certain potential carcinogens may require additional handling requirements similar to chemical carcinogens including; initial delivery of the material to Materials Management, actual inspection and opening of the package by a Health and Safety Technician in a controlled environment, and storage of the material in double containers in a locked cabinet.

All employees who work with carcinogens receive information and training so that they may work safely and understand the relative significance of the potential hazard they may encounter.

Magnetic Fields

LLNL has established guidelines for dealing with steady-state (nonvarying) magnetic fields such as direct current electric and sub–radio frequency fields (Health and Safety Manual Supplement 26.12). The guidelines are designed to limit potential exposures by restricting access to authorized personnel only and limiting the duration of exposures.

Lasers

Most lasers are capable of causing eye injury to anyone who looks directly into the beam or its mirror reflection. In addition, high power laser beams can burn exposed skin. Lasers are classified into four categories based on their potential impacts to human health. Class 1 lasers are not capable of causing damage to human health. Class 2, 3, and 4 lasers may cause damage to the eyes if viewed directly or as a result of reflection. Class 3 and 4 lasers also pose a hazard to the skin from direct beams and reflections. Each employee who operates Class 3(b) or 4 lasers is required to have an eye examination, complete a laser safety training course, read and understand the Facility and Operational Safety Procedures, and complete any other training required by the employee's division or department. Operational Safety Procedures are required for many laser operations involving Class 2, 3, and 4 lasers, and engineering controls are implemented to ensure that the beam is controlled and incidental exposures are limited (LLNL, 1990e).

Class 3 and Class 4 lasers include those with a broad range of radiant powers and energies, from those with minimal potential for causing eye hazards to those capable of causing severe skin burns and significant eye injury. Worker exposure is limited by controlling access to the area, conducting a baseline eye examination, posting warning signs and labels, and installing warning devices and safety interlocks on doors to control access. In addition, for many Class 3 and Class 4 lasers, the entire beam path is enclosed and equipped with an interlock that prevents operation of the laser system unless the enclosure is properly secured. In instances when Class 3 and 4 lasers are outside enclosures, Operational Safety Procedures (OSPs) are required; for Class 3 lasers, OSPs may be required.

There were only two incidents reported in 1990 involving lasers. No injury resulted from these incidents (LLNL, 1991i).

There has been one case since 1986 in which a worker was injured while working with a laser. A technician who was not wearing eye protection experienced retinal bleeding and permanent eye damage when a laser beam reflected into the technician's eye.

Noise

Employees exposed to noise levels in excess of those allowable by LLNL (and OSHA) standards (85 dBA) must be placed on a hearing conservation program. They are provided with hearing protection devices (earplugs and earmuffs) and instructed on noise hazards and the proper use of hearing protection. The employees are also placed on a regular schedule of audiogram tests to assess and monitor the onset and development of hearing loss. The Hazards Control Department supports LLNL personnel by measuring existing levels and exposures, or by making suggestions about noise control (Schweickert and Rosen, 1984). The preferred approach is to use engineering controls to reduce or eliminate any potentially harmful sources of noise.

San Joaquin Valley Fever

Anyone who works at or visits LLNL Site 300 may be exposed to an organism that causes Valley Fever (coccidioidomycosis), a respiratory infection common throughout the San Joaquin Valley. Several procedures are in place to ensure that workers are informed of the potential risks. Before a work assignment at LLNL Site 300, each employee or prospective employee undergoes a skin test to determine if the individual has developed immunity to Valley Fever. Based on the results of the test, and other physical factors (e.g., greater susceptibility, or being pregnant), the employee or prospective employee will be counseled concerning their increased risk and the Health Services Department will recommend that the individual should or should not work at LLNL Site 300 (LLNL, 1990f).

Biological Materials

Certain biological materials used or handled at LLNL are potentially hazardous. These materials are generated as a result of clinical/emergency and research activities. Individuals can be exposed to biohazards as a result of patient care procedures, and the collection, handling, processing, and disposal of various human body substances (e.g., blood, tissues) that may harbor pathogens. The potential exposure of workers at LLNL to practices documented in the health and safety manual. In addition, whenever possible all contaminated laboratory equipment and tools are sterilized prior to discarding or washing (LLNL, 1990c).

Various safety standards have been established to assure that proper facilities and procedures are employed while working with biological materials with varying degrees of potential hazard. All work on biological materials is conducted in appropriate facilities according to the potential hazard, in the Biomedical Sciences Buildings and the Health Services Clinic. Safety Level 1 refers to the standard laboratory practices, equipment, and facilities designed for any work with biological material. This safety level is appropriate for experiments involving agents of known or minimal potential hazard to laboratory personnel and environment.

Safety Level 2 refers to laboratory practices, equipment, and facilities designed for experiments with agents of moderate potential hazards to personnel and environment. It differs from Safety Level 1 mainly in that in addition to open bench areas appropriate for general work with biological material, it provides containment to carry out certain laboratory experiments and operations (LLNL, 1990c).

Safety Level 3 refers to laboratory practices, equipment, and facilities suitable for experiments involving agents of high potential risk to personnel and environment. Requirements for Safety Level 3, in addition to Safety Level 2 requirements, include facility access control, use of personnel protective equipment, confinement of all work within biological safety cabinets, and protection of vacuum line by liquid traps and HEPA filters (LLNL, 1990c).

Safety Level 4 refers to laboratory practices, equipment, and facilities suitable for experiments involving agents that present a high-risk of life-threatening disease. Currently, no work classified at this safety level is authorized at LLNL (LLNL, 1990c).

Additional guidelines have been developed for handling laboratory animals and research activities involving the use of clinical specimens, (e.g., human blood). Employees who work with potentially pathogenic microorganisms, human cells, or other samples that may contain infectious agents, have their blood serum sampled by Health Services as a baseline for future assay in the event of accidental exposure (LLNL, 1990c).

Occupational Safety

Occupational safety was evaluated through a review of recorded occupational injuries from 1985 through 1990. Information on these injuries is contained in the document "LLNL Safety Experience 1990" (LLNL, 1991i). Occupational injuries are recorded as the number of cases per 200,000 hours, or approximately 100 person-years worked. In comparison to other DOE research contractors, LLNL ranks 20th of 32 for the rates of lost or restricted workdays.

Five-Year Trend Data (1986–1990)

The following trends for occupational injury were identified for LLNL.

• The number of total recorded cases per 200,000 hours worked was 2.1 in 1990 compared to the 5-year DOE average of 2.1 from 1986 through 1990.
• The number of cases per 200,000 hours worked involving lost or restricted workdays was 2.3 in 1990 compared to DOE 5-year average of 1.1 from 1986 through 1990.
• The number of incidents involving electrical shock was 42 cases in 1990 compared to the 5-year average of 34 from 1986 through 1990.
• The number of onsite vehicle accidents per million vehicle miles was 3.0 in 1990 compared to the 5-year average of 3.9 from 1986 through 1990.

There were 169 recordable injuries (i.e., injuries that require medical attention beyond first aid and are reported to DOE) at LLNL in 1990, resulting in 4081 lost and restricted activity workdays. Of these injuries, overexertion (e.g., muscle strains, back strains) contributed 49 percent, wounds contributed 29 percent, cumulative trauma (e.g., carpal tunnel syndrome) contributed 15 percent, skeletal injuries contributed 3 percent, and injuries listed as "other" contributed 4 percent.

In order to reduce the number of occupational injuries, LLNL has taken measures to increase both the amount and frequency of safety training. During 1990, the Hazards Control Department presented 876 health and safety courses; total attendance for these courses was 16,465 people. The number of courses has steadily increased over the past 5 years, from a low of 400 courses taught in 1986. In 1990 the Health Services Department and the Hazard Control Department also presented 164 classes to 1280 workers (topics included first aid, cardiopulmonary resuscitation, and back care) (LLNL, 1991i).

Specific Accident Information from 1987–1991

In addition to routine exposures, unusual occurrences may result in worker exposures to toxic substances and other physical hazards (e.g., electrical shock). When certain types of incidental accidents occur, LLNL is required to document them in environmental incident and/or unusual occurrence reports, and to transmit them to DOE and in some cases other state and federal agencies. There were 14 occurrences at LLNL in the 5 years from 1987 through 1991, as reported in occurrence and incident reports, that resulted in workers being taken to the hospital or to the Health Services Department.

• In January 1987, a technician was injured while performing an experiment with high explosives. The employee received cuts to both arms from glassware fragments when a small explosion occurred after he twisted a joint containing a glass condenser and a glass reaction vessel. The employee was treated and released the same day (LLNL, 1991l).
• In August 1987, there was a spill of fuming chlorosulfuric acid in the Hazardous Waste Management facility which resulted in a mild injury to the operator. Approximately 8 ounces of the material was spilled onto the paved area in the facility and on his clothes. The spill resulted in burns on the thighs and hands of the operator. The employee was treated and released (LLNL, 1991l).
• In August 1987, a technician was injured while reloading a copper laser head. While the technician was disassembling the pressurized laser head, a retaining ring struck the technician in the face. The employee was treated and released (LLNL, 1991l).
• In April 1988, two different groups of people received medical care after being exposed to acids. An eruptive reaction occurred while personnel were bulking various acids in a 55-gal acid compatible drum in the Hazardous Waste Management area. A small amount of the mixed acid formed a vapor cloud and moved downwind. Five people in Building 614 were treated for minor injuries from the cloud. Three of the five received treatment from an ophthalmologist for eye irritation. The fourth person reported respiratory difficulty and was sent to a local hospital for observation. The fifth person reported a minor skin exposure. Forty-one other people received medical counseling for employees concerned with potential exposure and were released (LLNL, 1991l).
• In November 1988, two people were taken to receive medical care after an explosion occurred while an experiment was being performed using polymers (LLNL, 1991l). The employees were treated, released, and went back to work.
• In July 1989, four workers were exposed to hydrogen chloride, chlorine, and phosgene gas and were taken to the hospital to be observed. The workers were exposed to chemicals (i.e., freon breakdown products) during the refurbishment of a copper laser. The employees were released and returned to work the same day (LLNL, 1991l).
• In January 1990, a technician was exposed to chemical vapors while segregating chemical waste at Building 231. The vapors originated from a container that was not capped properly. The technician experienced a dry throat and dizziness roughly 10 minutes after smelling the fumes. The technician was examined and hospitalized for 24 hours for observation. Three other workers with similar but less severe symptoms were examined by LLNL medical staff and released (LLNL, 1991l).
• In January 1990, an employee was installing a replacement hoist and was exposed to an electrical arc flash 6 to 8 ft from his eye. The employee was attempting to repair a crane and found a loose electrical wire that subsequently arced. The employee was wearing no eye protection. The employee was examined by LLNL Health Services and returned to work (LLNL, 1991l).
• In September 1990, an employee fell while attempting to disconnect a water hose on a piece of equipment. The hose unexpectedly came loose, and the employee fell backward, breaking her femur. She was then taken to the hospital for treatment (ORP, 1991).
• In September 1990, an employee was using the basket of a bicycle to carry materials. While he rode, the materials slipped into the spokes and brought the bicycle to an abrupt stop. The employee flew forward and landed on his wrists and arms, resulting in fractures in both arms. The employee was treated for his injuries (ORP, 1991).
• In November 1990, an employee fell asleep while driving; the vehicle left the roadway and collided with a traffic signal pole. The driver was taken by ambulance to a local hospital, treated for slight injuries, and released (ORP, 1991).
• In November 1990, three personnel were injured in an automobile accident. In the process of executing a left turn, the driver's hand slipped from the steering wheel and the pickup truck hit a steel fence. The driver and passengers of the vehicle received medical treatment for minor injuries (ORP, 1991).
• In November 1990, a technician was injured as a result of striking a cabinet. As he was checking the temperature of a battery unit, the technician felt a shock. In reflex, he raised his left arm and struck a battery cabinet; his left hand made contact with another battery. The technician was admitted to the hospital for observation (ORP, 1991).
• In November 1990, an employee driving an LLNL vehicle was making a right turn from a stop when her vehicle was struck from the rear by another employee. The driver of the LLNL vehicle sustained minor injuries and was transported to the hospital for treatment (ORP, 1991).

Table C-2 Internal Radiation Exposures (Other Than Tritium) for 1980 Through 1990

Year of Intake	Building Number	Number of People	50-Year Committed Effective Dose Equivalent
1983	332	1	0.17 rem
1986	332	2	1.02 rem
			0.97 rem
1988	251	1	2.03 rem

Source: Mansfield, 1991.

Table C-3 Instances Where Air Concentrations Exceed OSHA Permissible Exposure Limits & Time-Weighted Averages^a in 1990

Metal	Measured Concentration (mg/m3)	Permissible Exposure Limit—Time Weighted Average(mg/m3)
Beryllium	0.0035b	0.002
Chromium	1.6c 1.2	1.0 Chromium
Iron	6.7 5.1 89.0 7.6	5 Iron Oxides
Nickel oxide	14.0	0.1 Nickel metal and other compounds
Uranium	1.21d	0.2 Uranium (insoluble)

^a LLNL uses limits that are equivalent or more protective than OSHA. OSHA limits are provided only for comparison.
^b This was an area sample that was not representative of employee exposures.
^c Fumes from oxygen-cutting/welding operations. Ventilation systems were recently upgraded.
^d This uranium concentration was within a ventilated enclosure. Workers were outside the enclosure wearing full-face respirators.

C.3.1.3 Epidemiologic Studies

In the late 1970s, the onsite Medical Director observed an unusually large number of LLNL employees with malignant melanoma. In 1976 this finding was reported to the Resource for Cancer Epidemiology of the California Department of Health Services. The Resource for Cancer Epidemiology published an initial paper in 1980 documenting the elevated levels of malignant melanoma among LLNL employees. LLNL established a Melanoma Investigation Task Group to further investigate the increased reporting of melanoma among employees. Numerous independent studies have been conducted by the Resource for Cancer Epidemiology and other study groups to evaluate this elevated incidence and to try to identify potential causes. To date, these studies have been unable to definitively correlate the increased malignant melanoma incidence with any occupational or environmental factors at LLNL. However, LLNL's Melanoma Investigation Task Group continues to coordinate several ongoing research efforts to identify the reasons for the apparent increase.

The theories considered by researchers and the Biomedical Sciences Division at LLNL as possible causes for the elevated levels of malignant melanoma include:

• statistical chance;
• occupational factors;
• an infectious agent;
• unique exposure to sun among LLNL employees; and
• increased reporting of early cases due to increased surveillance.

It is doubtful that the large increase in cases of malignant melanoma at LLNL occurs purely by chance. It is also unlikely that a unique infectious agent, which has never before been documented, is present at LLNL or that the employees of LLNL are unusually susceptible to solar exposure. Employees of other facilities which have similar populations and solar conditions and which conduct similar operations, such as Los Alamos National Laboratory, have not shown an elevated level of malignant melanoma (Acquavella et al., 1982). Although each of the possible reasons for the increase listed above has been considered and, in some cases, investigated, the bulk of the research has focused on occupational factors and the increased surveillance of the Laboratory community. Studies of past employees of LLNL indicate that the high incidence of malignant melanoma is a relatively recent problem which was not evident before the 1970s (Moore, Bennett, and Mendelssohn, 1984; Moore and Bennett, 1984).

A DOE Committee was formed to review the results of the original 1980 Resource for Cancer Epidemiology study. DOE Committee concluded that the incidence of malignant melanoma among LLNL employees was three to four times as great as that observed in the surrounding two counties during the period from 1972 through 1977. A Resource for Cancer epidemiology case-control study reported a relationship between the elevated level of malignant melanoma and five occupational factors associated with work at LLNL (Austin and Reynolds, 1984). These factors identified in the 1984 study included exposure to radioactive materials, exposure to volatile photographic chemicals, work at LLNL Site 300, presence of affected workers at the Pacific Test Site at the time of a nuclear event, and working with chemicals. Following the publication of this report, the conclusion that these factors are responsible for the increase in malignant melanoma at LLNL has been questioned by a number of groups. The data was reanalyzed by a team from the University of North Carolina and a review panel of melanoma experts from around the world. These groups both found fault with the conclusions of the Resource for Cancer Epidemiology report and did not believe that a causal link could be drawn between these five factors and the increased incidence of malignant melanoma at LLNL (Moore, Bennett and Mendelssohn, 1984; LLNL, 1989b). The group from the University of North Carolina concluded, however, that work near radioactive material and volatile photographic chemicals and work at LLNL Site 300 were "strongly associated" with incidence of malignant melanoma. The small number of cases available for study makes it difficult to adequately analyze the available information and lends uncertainty to the results. However, as mentioned earlier, studies at Los Alamos National Laboratory, which has similar occupational and environmental conditions to LLNL, have shown no increase in malignant melanoma among employees (Acquavella et al., 1982). In addition, extensive research on the effects of radiation on the incidence of cancer have not shown a dose-dependent increase of malignant melanoma (Moore, Bennett, and Mendelssohn, 1984; Hiatt and Fireman, 1986). The Resource for Cancer Epidemiology study (Austin and Reynolds, 1984) concluded that the characteristics of the malignant melanoma cases at LLNL are generally unremarkable in terms of location, virulence, and other factors.

Several recent studies have focused on the possibility that the incidence of malignant melanoma is actually due to the increased surveillance of LLNL employees following the outbreak of cases in the 1970s and an increased awareness of the disease. These studies have focused on several possible ramifications of this increased surveillance. One possibility is that early identification of cases in the first stages of development resulted in an early peak of cases and will be reflected in a reduction of the rate of incidence to normal levels over time. The diagnosis of very small skin lesions as malignant melanoma may have led to the subsequent treatment of early lesions which may not have progressed and would not have otherwise been reported as cases of malignant melanoma.

A study published in June 1990 (Schneider, Moore, and Sagebiel, 1990) indicates an increasing trend of early diagnosis of malignant melanoma at LLNL and supports the theory of increased surveillance. The study compared the thicknesses of malignant melanoma lesions, a sign of how far the disease has progressed at the time of diagnosis, from LLNL and those from a local histopathology laboratory. The researchers found that the lesions from LLNL were consistently thinner at the time of diagnosis than those from the local laboratory and that the thickness of the lesions has been dropping at a faster rate at LLNL than in the surrounding community.

The results of a study that compared members of the Kaiser Permanente Medical Care Program who were employees of LLNL with those who were not LLNL employees also support the theory of increased surveillance (Hiatt and Fireman, 1986). The study found that after the initial publicity concerning malignant melanoma at LLNL in 1977, employees were three times as likely to have biopsies of lesions and skin discolorations as non-employees.

The results of these studies imply that the publicity surrounding malignant melanoma at LLNL has produced a greater surveillance of LLNL employees and is resulting in the earlier identification and treatment of malignant melanoma. The question that remains is whether all of the lesions detected as a result of this surveillance would have progressed to a more advanced state and eventually been detected anyway. If some had not progressed, they may not have been detected under normal surveillance conditions (outside LLNL), and this may explain part or all of the prolonged elevation of the malignant melanoma rate at LLNL.

The high degree of surveillance at LLNL and the early detection of the disease explains the relatively low level of mortality from malignant melanoma observed during a mortality study performed at LLNL (Moore, Bennett and Mendelssohn, 1984; and Moore and Bennett, 1984). In addition to the conclusions concerning malignant melanoma, this study indicated that mortality resulting from all types of cancer at LLNL is below the expected value and that the total mortality for all causes at LLNL is slightly more than half the value expected. These conclusions are based on comparisons with national vital statistics. The 5-year survival rate of all malignant melanoma cases at LLNL is 87 percent, and the rate has increased to 96 percent in those cases diagnosed since 1977 (LLNL, 1989b). An additional study published in 1985 found that the overall incidence of cancer among LLNL employees is no different from the general population in the San Francisco Bay Area (Reynolds and Austin, 1985).

A study is currently being performed by the Northern California Cancer Center to assess the possibility that the elevated incidence of malignant melanoma reported at LLNL may actually be due to an underreporting of cases in the surrounding populations. Initial estimates are that 10 to 20 percent of malignant melanoma cases in the vicinity of LLNL are not reported to the local tumor registry (LLNL, 1989b). This problem is especially difficult in cases of malignant melanoma because less serious cases are often treated by dermatologists in their offices and do not require major surgery. Although this problem may be contributing to the apparent elevation of malignant melanoma incidence at LLNL, it is doubtful that it will fully explain this elevation.

A status report, published by the Melanoma Investigation Task Group in 1989, indicated that there was a reduction of malignant melanoma cases diagnosed in the last several years of that decade (LLNL, 1989b). The rate at LLNL was still twice the rate of the surrounding community, but it appeared to be dropping from the level observed during the late 1970s and early 1980s. At the time of the report, these results were not statistically confirmed. The report also stated that LLNL was aware of only one death from malignant melanoma among active employees since 1983.

LLNL continues to be involved in several ongoing studies that will help to shed additional light on the questions surrounding malignant melanoma among LLNL employees. These projects include the investigation of the questions of underreporting of malignant melanoma in the local community, additional pathological analyses of lesions, and extensive comparisons and interviews with workers at LLNL who have developed malignant melanoma.

C.3.2 SNL, Livermore

C.3.2.1 Radiation Exposures

The only source of frequent occupational internal exposure at SNL, Livermore is the Tritium Research Laboratory (Building 968). The work areas at this facility are monitored continuously for tritium. In addition, all workers in the building have weekly bioassays to monitor internal exposures to tritium, and additional bioassays are taken for workers when room air monitors or routine work area contamination surveys indicate a potential exposure from unanticipated increases in ambient levels of tritium. The maximum dose equivalent received by any individual at Building 968 in 1990 was 0.20 rem, 4 percent of the annual dose limit of 5 rem (DOE, 1988c). The summation of doses received by all workers, or the collective dose, was 1.05 person-rem. Figure C-8 shows the maximum individual and total collective occupational doses due to tritium exposures for 1986 through 1990 at Building 968.

From 1986 through 1990 there were two cases in which two workers at SNL, Livermore had positive bioassays for radionuclides other than tritium. Both of these exposures occurred during the handling of depleted uranium. Both bioassays indicated that uranium concentrations in the urine were less than 10 micrograms per liter, which is below the threshold requiring further action (15 µg/L) and less than one-tenth of the levels where the chemical toxicity causes measurable effects on the kidneys. No further actions were taken with respect to these two exposures.

Thermoluminescent dosimeters are used at SNL, Livermore to monitor exposures to external sources of radiation. These dosimeters are issued to each employee who has the potential to receive a radiation dose of more than 0.1 rem per year and to employees who are recommended for personnel monitoring by their supervisor. During 1990, the highest individual radiation dose was 0.24 rem, or 4.8 percent of the annual dose limit of 5 rem (DOE, 1988c). The summation of all radiation doses from external exposures, the collective dose, at SNL, Livermore totaled 2.4 person-rem. The majority of SNL, Livermore employees do not receive any measurable external radiation exposures above background levels (SNL, Livermore, 1990a). Figure C-9 shows the average distribution of ollective doses from external exposures at SNL, Livermore for 1988, 1989, and 1990 (SNL, Livermore, 1990a).

In addition to the radiation exposures that may occur as a result of the day-to-day operations at SNL, Livermore, workers may be exposed to radiation as a consequence of inadvertent incidents or unusual occurrences. Inadvertent incidents that fall under the category of "unusual occurrences," as defined by DOE Order 5000.3A, are required to be reported to DOE. The reports from inadvertent events and unusual occurrences were reviewed to determine the contribution of such incidents to the occupational radiation exposures at SNL, Livermore.

In July 1984, approximately 2.5 curies of tritiated water vapor was released into a room at the Tritium Research Laboratory due to a cracked, certified high pressure gas, stainless steel nipple. The incident resulted in a radiation dose equivalent of 1.65 rem to one individual and 0.15 rem to another; five others received less than 0.05 rem.

In August 1987, personnel conducting tritium unloading and sample recovery at the Tritium Research Laboratory were exposed when they assumed that the tritium had been completely unloaded from a high pressure vessel. When the container was opened, about 1100 Ci of tritium gas was released into the room and exhausted up the stack into the environment. The operator received an effective dose equivalent estimated to be 0.015 rem compared to the annual dose limit of 5 rem for radiation workers. Monitoring indicated no deposition of tritium in the area surrounding the Laboratory. There was a potential effective dose equivalent commitment of 10^-4 mrem to a hypothetical member of the general public at the site boundary, compared with the dose limit of 10 mrem for nonaccidental release to the atmosphere.

C.3.2.2 Toxic Exposures and Physical Hazards

The purpose of this section is to identify toxic materials and physical hazards present in the workplace at SNL, Livermore and to discuss various control procedures in limiting the risks to workers from these agents. Work performed at SNL, Livermore encompasses research and development necessary for the engineering design of components for nuclear and conventional weapons, and also encompasses research supporting national energy programs. The wide range of research conducted at this facility makes a large and varied inventory of chemical and physical agents necessary to support the experiments that are conducted. This includes numerous hazardous chemicals in liquid, particulate, gas, or vapor form, and physical agents such as electromagnetic radiation, lasers, and magnetic fields. Other environmental stresses such as noise and ergonomic factors (e.g., repetitive motion, mental or physical fatigue) create health concerns when exposures are uncontrolled. Since this is a research facility, exposures to chemical and physical agents are generally intermittent rather than continuous in nature, occurring while workers perform experiments and tests.

At SNL, Livermore, employee safety and health has been addressed through the development of the Environment, Safety, and Health Manual (SNL, Livermore, 1991b). This manual outlines the steps taken at SNL, Livermore to implement a comprehensive health and safety program for all employees as well as for the environment. Safety and health issues are addressed at SNL, Livermore through the preparation of preliminary hazard assessments and standard operating procedures. Chemicals introduced into a laboratory or work area are accompanied by a material safety data sheet (MSDS). These data sheets provide detailed information on the physical, chemical, and physiological properties of a particular chemical and recommended control procedures to be used during handling. The material safety data sheets are kept in a binder in the work area where the chemicals are used. Hazards communication training includes instruction on using the MSDS and is provided for all employees. Additional training for spill control and chemical safety and hazardous waste classes are also required for specific work areas.

During the initial planning for a laboratory or operation, preliminary hazard assessments are prepared to evaluate and document the potential hazards associated with the proposed operation. If it is determined that the hazards can be effectively controlled, the activity is permitted to proceed after preparing a standard operating procedure. The standard operating procedure is a detailed report that describes the means of mitigating the hazards described in the preliminary hazard assessment. Both of these documents receive management approval and are updated periodically.

Industrial Hygiene

The role of the Industrial Hygiene section of the Health Protection Department is to directly support supervisors in the identification, evaluation, and control of environmental factors and stresses found in the work place, and to develop programs to comply with governmental health regulations. These programs include the control of hazardous chemicals, a respiratory protection program, a hazard communication program, a laser and visible light program, a noise and hearing protection program, and a confined space entry program. The Industrial Hygiene Section is also responsible for conducting workplace evaluations for chemical and physical exposures. There were no recorded occupational injuries or illnesses due to chemical exposures during the 4-year period from 1987 through 1990, indicating that these types of exposures are being adequately controlled (SNL, Livermore, 1991f).

Those employees whose work routinely exposes them to low levels of toxic or carcinogenic materials are placed on a special medical monitoring program. The Industrial Hygiene Organization also monitors the workplace to ensure that appropriate protective measures are in place and exposures are kept as low as reasonably achievable.

Toxic Chemicals

It is the responsibility of any individual ordering chemicals at SNL, Livermore to ensure that the toxic properties of the chemicals have been assessed and that adequate precautions will be taken when using them. The Health Protection Department reviews all requests for chemicals obtained by a purchase requisition form and is responsible for ensuring that workers are adequately trained. Upon review of the requisitions, the Health Protection Department may require additional information from the line organization user to ensure that proper control measures will be used when working with the requested hazardous material. Exposure monitoring is initiated for any substance regulated by a standard which requires such monitoring or when exposures may exceed permissible exposure limits. This occurs when the Industrial Hygiene section determines that exposure levels for a regulated chemical may exceed a designated action level such as the Occupational Safety and Health Administration (OSHA) permissible exposure limits (PELS). Exposure monitoring consists of identifying and evaluating sources of exposures, and then measuring chemical concentrations. Employees are notified of the results of chemical monitoring within 15 working days after the receipt of any monitoring results (SNL, Livermore, 1991j).

The major portion of the chemicals used at SNL, Livermore is distributed among six buildings. Small quantities of chemicals (e.g., liquid and gaseous fuel) are used in the combustion research facility, Building 906, and two laboratories, Buildings 913 and 916. In the shop, Building 913, and plant maintenance, Building 963, small quantities of chemicals, oils, greases, and solvents are used.

Carcinogens

At SNL, Livermore, chemical carcinogens are used by Laboratory employees only when required by the specific research project and no other practical substitutes can be found. When the use of chemical carcinogens is unavoidable, every effort is made to minimize employee exposure to levels as low as reasonably achievable and to limit the size of the work area. Any work involving the use of chemical carcinogens must follow specific procedures for: purchasing and receiving, posting and labeling, packaging and storage, inventory, and decontamination and disposal. Proper employee education, training, and medical surveillance are also a part of the general requirements for usage of chemical carcinogens.

The use, synthesis, and storage of carcinogens must be evaluated by an industrial hygienist. Chemical use, the quantity of material involved, and the control measures engaged require a safe operating procedure. For certain highly potent carcinogens, the industrial hygienist may request the user to maintain a log of the chemical and the quantity used and may require controlled access to the area.

The purchasing and receiving of chemical carcinogens is controlled by several factors. Laboratory guidelines restrict the purchase of these chemicals to only the amount of material necessary for the specific project. Authorization to purchase and use such chemicals requires the user to show the safe operating procedure to obtain approval from the industrial hygienist. Unless approved by the industrial hygienist, carcinogens cannot be ordered.

Training for the handling and disposal of carcinogens is done through the Center for Environmental Safety and Health and Facilities Management. All employees who work with carcinogens receive information and training so that they may work safety and understand the relative significance of the potential hazard they may encounter.

Electromagnetic Radiation

A device capable of generating energy of wavelengths longer than 10^-7 m in the electromagnetic spectrum is classified as a nonionizing energy source. SNL, Livermore complies with the appropriate occupational exposure standards (i.e., American National Standards Institute Radio-Frequency Protection Guide, and American Conference of Governmental Industrial Hygienists Threshold Limit Values). Based on these standards, SNL, Livermore has adopted primary health protection standards. Hazard warning signs are required to be posted at access points to those areas where radio-frequency field levels exceed permissible limits (SNL, Livermore, 1991d).

SNL, Livermore maintains an inventory of radio-frequency/microwave generating sources. As part of the control procedures, radio-frequency/microwave user organizations must prepare an inventory of the radio-frequency/microwave-generating equipment that potentially expose personnel to hazards.

Engineering controls are given primary consideration in mitigating or eliminating human exposure to radio-frequency/microwaves. Administrative and procedural controls are employed only if they afford the necessary degree of protection to maintain personnel exposures at or below acceptable levels and if engineering controls are not feasible or cannot effectively control the hazard. In cases where administrative/procedural controls are used, documentation is available to justify this approach (SNL, Livermore, 1991g).

Noise

Exposure to noise over a period of time can permanently impair hearing. The hearing conservation program at SNL, Livermore ensures that workplace noise does not damage employee hearing. Annual employee physical examinations include tests for hearing impairment (SNL, Livermore, 1991d).

A program of workplace monitoring is also in place to identify potentially hazardous noise levels. Employees exposed to noise levels in excess of those allowable by applicable standards are placed in a hearing conservation program. This program consists of regularly scheduled audiogram tests to assess and monitor the development of hearing loss. In addition, employees are provided with hearing protection and instructed in noise hazards and the proper use of hearing protection. Engineering controls are preferred to reduce the potential exposure to noise (SNL, Livermore, 1991d).

Occupational Safety

Occupational safety at SNL, Livermore was evaluated through a review of the Occupational Safety and Health Administration (OSHA) 200 Logs submitted from 1986 through 1990. OSHA 200 Logs contain summary information on the number and type of accidents occurring during a calendar year, as well as the number of lost and restricted activity workdays (SNL, Livermore, 1991f).

Five-Year Trend Data (1986–1990)

The following trends in occupational injuries were identified at SNL, Livermore:

• The number of total recorded cases per 200,000 hours worked was 3.52 in 1990 compared to the 5-year DOE average of 2.1 from 1986 through 1990.
• The most commonly reported injuries during this period were lacerations (36 percent) and back strains (28 percent).

Specific Accident Information from 1987–1991

There were 35 occupational injuries reported at SNL, Livermore in 1990, resulting in 81 lost workdays and 91 days of restricted activity. Of these injuries, lacerations contributed 34 percent, back and muscle strains contributed 20 percent, contusions contributed 11 percent, and foreign matter in eyes contributed 11 percent.

The Center for Environment, Safety, and Health and Facilities Management is responsible for the design, development, and presentation of all generic and environment, safety, and health training. Generic training, such as site orientation, chemical safety, and electrical safety, is required for employees who are new to the area (SNL, Livermore 1991b).

In addition to routine exposures, unusual occurrences may result in worker exposure to toxic substances and other hazards (e.g., burns). There have been three occurrences at SNL, Livermore in the last 5 years (1987–1991 occurrence reports) that have resulted in workers receiving medical treatment.

• In January 1987, during a security exercise, an individual was injured as a result of the discharge of a training weapon. The individual received a small burn on her neck. She received medical care and then was released (SNL, Livermore, 1992).
• In February 1987, there occurred an inadvertent ignition of pyrotechnic material as a result of drilling. The emitted sparks caused the operator to sustain minor burns on several fingers. The employee received medical treatment (SNL, Livermore, 1992).
• In May 1991, an employee noticed an "ammonia-like" odor. A security inspector entered the building to ensure that there were no other people there. A second security inspector observed through the doorway that the first officer had fallen to his hands and knees approximately 5 yards inside the door and seemed to be having difficulty breathing. The second inspector instructed the employee to pull the building evacuation alarm, then entered the building and pulled the first inspector outside. The affected security inspector was treated and transported to the hospital for observation. The building is an office building. The source of the odor was a floor wax that was being applied by a janitorial floor-wax crew (ORP, 1991).

C.3.3 Radiation Risk Assessment

The principal adverse effects from human exposures to low-level ionizing radiation are carcinogenicity (ability to cause cancer), mutagenicity (ability to cause genetic or inheritable defects), and teratogenicity (ability to cause noninheritable birth defects) (EPA, 1989b). For low level exposures, the most significant risk is that of latent cancer. Genetic effects can be induced during the reproductive period, which is considered to last for approximately 30 years. Teratogenic effects can be induced only during gestation.

When large numbers of persons are exposed to ionizing radiation, the number of fatal cancers that result can be estimated by considering the radiation doses received, the number of persons, and the age distribution of the exposed group. The summation of the radiation doses, or the collective dose, provides the basis for this estimation. The number, called the risk estimator, is multiplied by the measured or calculated effective dose equivalent to estimate the chance of latent fatal cancers that can be attributed to the exposure.

Not all cancers are fatal; therefore, the risk estimator for fatal cancers must be modified to account for the induction of both fatal and nonfatal cancers from radiation exposures. In addition, hereditary effects during the first two generations are normally considered.

During the past several years, there has been a continuing upgrade and an extensive review by the Radiation Effects Research Foundation of the dosimetry and cancer induction among survivors of the atomic bombings at Hiroshima and Nagasaki. The National Academy of Sciences—National Research Council's Committee on the Biological Effects of Ionizing Radiation (BEIR) then reviewed this information, along with other sources of information on the effects of low levels of ionizing radiation. The BEIR review was recently published as BEIR-V, Health Effects of Exposure to Low Levels of Ionizing Radiation (BEIR-V, 1990). The analysis conducted by BEIR-V differed from previous reviews in several respects:

• More time has elapsed since the previous comprehensive analysis of the data provided by the Radiation Effects Research Foundation; therefore, there have been additional cases of fatal cancer.
• Changes were made in the estimates of radiation dose. Further physical modeling of the behavior of the bombs dropped at the two cities indicated that the neutron component of the total radiation field had been overestimated in previous TD65 dose estimates. Corrections in the radiation exposure field reduced the radiation dose estimates.
• The data were analyzed using a relative risk transfer model rather than the absolute risk transfer model used in previous BEIR evaluations.

The International Commission of Radiological Protection (ICRP) defines total detriment as the total number of deleterious effects (fatal and nonfatal cancers, severe hereditary effects, other deleterious effects, and the associated morbidity) that would eventually be experienced by persons exposed to ionizing radiation and by their descendants. Estimates made by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), the ICRP, and the National Council on Radiation Protection and Measurements yield a nominal value of 10^-3 per rem as the risk of developing a fatal cancer from acute high dose exposures (ICRP, 1991; UNSCEAR, 1988; NCRP, 1987). When dose and dose-rate effectiveness factors are considered, the various groups arrive at values of 3×10^-4 to 5×10^-4 per rem as the risk of inducing fatal cancer in a population of all ages. The International Commission on Radiological Protection has recently published new cancer risk estimators in International Commission on Radiological Protection Publication 60 (ICRP, 1991). For low levels of radiation exposure of the type experienced as a result of LLNL and SNL, Livermore operations, the new ICRP risk estimator for induction of fatal cancer is 0.0005 per rem of effective dose equivalent. Allowing for nonfatal cancers, severe hereditary effects, and other deleterious effects, the risk estimator for total detriment is 0.00073 per rem of effective dose equivalent.

At the 1991 Annual Meeting of the National Council on Radiation Protection and Measurements, both Dr. Warren Sinclair, the outgoing president, and Charles B. Meinhold, the incoming president, announced that they would also be revising National Council on Radiation Protection and Measurements Report No. 91 (NCRP, 1987) to include the new National Council on Radiation Protection and Measurements risk estimators and that the values for induction of fatal cancers will be 0.0003 to 0.0004 per rem of effective dose equivalent.

Both the U.S. Environmental Protection Agency and the U.S. Nuclear Regulatory Agency have used risk estimators within the range recommended by UNSCEAR, ICRP, and NCRP in the development of recent regulations (EPA, 1989d; NRC, 1991).

Thus, the risk estimators for fatal cancer induction are on the order of 0.0005 per rem of effective dose equivalent and approximately 0.00073 for total health detriment. Because of the uncertainty in the risk estimators, it is recommended by the ICRP that estimates of potential health effects be presented to only one significant figure.

Mr. Meinhold also announced that the National Council on Radiation Protection and Measurements would retain its concept of the negligible individual risk level, which is defined as "a level of average excess risk of fatal health effects attributable to irradiation below which further effort to reduce radiation exposure to the individual is unwarranted" (NCRP, 1987). The value recommended by the National Council on Radiation Protection and Measurements for the negligible individual risk level is 0.001 rem.

Table C-4 tabulates the internal and external radiation doses received by workers at LLNL and SNL, Livermore during 1990.

The table also presents calculation of the chance of fatal cancer and total health detriment to the workers based on these radiation doses. The combined collective effective dose equivalent to workers at LLNL and SNL, Livermore during 1990 was 32 person-rem. Using the cancer risk estimators discussed above, the calculated chance that a single cancer will occur among all workers from 1 year of operation of the facilities is about 1 in 70 for fatal cancers and 1 in 50 for total health detriment. The National Academy of Sciences Committee on the Effects of Ionizing Radiation cautions that the risk estimates become very uncertain at very low doses and the actual risk may be zero (BEIR-V, 1990). For comparison, the radiation dose from background radiation to a population of 12,000 people is estimated to be about 3600 person-rem. The calculated number of fatal cancers resulting from exposures to background radiation is 1.8 and the number of total health detriment is 2.6.

Table C-4 Radiation Doses and Health Effects from Occupational Exposures in 1990

Site	Collective Dose (person-rem)	Chance of Fatal Cancer	Chance of Total Detriment
LLNL
Internal exposures at Building 331	0.5	0.00025	0.00036
External exposures at Building 332	19.6	0.010	0.014
Other external exposures	8.4	0.0042	0.0061
Total collective radiation dose:	28.5	0.014	0.021
SNL, Livermore
Internal exposures at Building 968	1.1	0.00055	0.00080
External exposures	2.4	0.0012	0.0018
Total collective radiation dose:	3.5	0.0018	0.0026
Combined Total: (LLNL plus SNL, Livermore)	32.0	0.016	0.023
Background Radiation*	3600	1.8	2.6

* Based on an annual background radiation dose of 0.3 rem per person to a population of 12,000.

C.3.4 Combined Risks

In assessing the safety of an operation it is important to compare the harm that may be caused by ionizing radiation with that caused by other agents (e.g., chemicals). The International Commission on Radiological Protection considers that any formal solution for adding the effects are impossible since "the various harmful effects of radiation are not only different in kind, but are likely to be regarded as of different importance by different individuals" (ICRP, 1977). Furthermore, radiation in combination with other physical and chemical agents may exhibit additive, synergistic, or even antagonistic effects depending on the agents and the conditions of exposure (NCRP, 1989). Similarly, human exposure to carcinogenic chemicals in combination with other chemicals (carcinogenic or noncarcinogenic) may result in additive, synergistic, or antagonistic effects, depending on the chemicals and the conditions.

In general, whole-body radiation appears to be carcinogenic for many, if not most, tissues of the body whereas specific carcinogenic chemicals generally induce cancers in a comparatively small number of target tissues (NCRP, 1989). The cancers developed by both radiation and chemical carcinogens are indistinguishable from those induced by other causes, and their induction can only be inferred on statistical grounds (NCRP, 1989).

Because of these limitations, and the low probabilities of health effects associated with operation of LLNL and SNL, Livermore, no attempt was made to combine the risks from ionizing radiation with those from other agents.