Operation Inferno
Operation Banish Beach

In spite of the failures of previous jungle-burning operations to produce suitable results and recommendations from agencies involved in the research and development of such operational concepts that the missions be terminated, further research was conducted in 1968 and 1969 to determine the specific limiting factors for forest fire initiation in humid tropical forests. Test fires and naturally occurring forest fires were observed and analyzed in Malaysia, Vietnam, Thailand, Bougainville, Australia, Puerto Rico, Hawaii, and the southeastern United States.

Two further jungle-burning operation were attempted after a forest fire started in the U Minh Forest in southern South Vietnam and raged for 10 days in April 1968. The U Minh Forest was a known enemy sanctuary area and had been the target of numerous operations. Observation of the fire reported secondary explosions believed to be from enemy supplies and there was significant interest in whether the effects could be extended or recreated. On 20 April 1968, Command in Chief, US Pacific Command (CINCPAC) requested that Commander, US Military Assistance Command, Vietnam (COMUSMACV) comment on the feasibility of creating similar fires in III and IV Corps Tactical Areas and in the Rung Sat Special Zone (RSSZ). COMUSMACV replied that the environmental factors in the areas of interest were no conducive to jungle burning as much of the terrain was inundated during high tide. In addition, the various factors contributing to the U Minh fires, a 3 month drought leading to extremely dry peat-like ground foliage and a favorable wind, could not be counted on, especially in the proposed target areas.

Despite these reservations, a number of missions were conduct during April 1968 as part of Operation Inferno. Unlike previous jungle burning operations that were primarily intended to destroy jungle foliage, the primary objective of Operation Inferno was to destroy enemy materiel. A secondary objective remained the large scale destruction of jungle foliage to deny the enemy a concealed safe haven. The concept of operations for Operation Inferno was to have cargo aircraft saturate the target areas with fuel oil (a mixture of JP-4 and diesel was used), which would then be ignited. The C-130s flew in a trail, 2,000 feet apart, at an altitude of 3,000 feet. The pallets of fuel oil filled drums were released at a pre-determined point.

Four missions were flown as part of Operation Inferno on 7, 27, 28, and 29 April 1968. For each mission, 14 C-130 aircraft dropped 64 55-gallon drums of fuel oil over the target areas. During the first mission napalm delivered by trailing strike aircraft was used to ignite the fuel. On later missions, a white phosphorus smoke grenade was attached to the pallets to ignite them. Pallets that did not ignite were to be ignited by Forward Air Controllers coordinating the mission using white phosphorus rockets. Visual observation confirmed large and intense, but ultimately localized fires that were not self-sustaining after the fuel had been consumed. It was suggested that with a favorable wind the fires might have been self-sustaining.

Throughout the summer of 1968, further operations were conducted as part of Operation Banish Beach. The tests continued to show that while the concept might be valid, it was impossible to control the various factors necessary for starting a successful self-sustaining fire. Seventh Air Force recommended on 31 July 1968 that the Banish Beach operations be canceled because of the usage of limited airlift resources, vulnerability of aircraft used in jungle burning operations to enemy fire, low accuracy of delivered fuel pallets, and the inability of the concept to provide significantly greater results over existing tactical air strikes. COMUSMACV after receiving comments from subordinate commands decided to hold the program in abeyance due to limited resources, inconclusive results, and the need to improve the concept A report by the US Forest Service in 1970 concluded that the concept was valid, but relied heavily on uncontrollable environmental factors. After Operation Banish Beach, no further jungle-burning operations were attempted.