Investigation report: Toxic gas release from the beta-gamma incinerator at the Savannah River Plant on December 9, 1986

On December 9, 1986, a scheduled functional test of the Halon fire suppression system in the Feed Lag Storage Area (FLA) of the BGI facility was initiated by manually activating the Halon system. Interlocks that shutdown ventilation in the FLA operated as designed, and the 756-lb charge of Halon 1301 was released into the FLA as intended. Normal building air flow designed to minimize spread of contamination, plus a momentary increase in pressure in the FLA resulting from the discharge of Halon, caused an estimated 450 lb of Halon to enter the adjacent process room through a number of small openings in the sheetmetal separating wall. About 240 lb of the Halon was drawn into the incinerator where it thermally decomposed into hydrogen fluoride and bromine. These gases were discharged through the incinerator stack. About 10:20 a.m., some employees, working approximately 1500 ft downwind, began to experience eye and respiratory irritation. An orange-yellow plume was observed to be coming from the BGI stack. At 10:28 a.m., S-Area supervision initiated an S-Area evacuation and notified plant management of the situation. At 10:33 a.m., the Halon test in the BGI was terminated and the FLA was opened and allowed to ventilate. At 10:50 a.m., it was determined that Halon decomposition in the BGI was the source of the irritating fumes and the incinerator was immediately shutdown. Approximately 10 S-Area Construction employees received first aid for respiratory irritation, and four were sent to an area hospital for evaluation. 9 figs