Text For Citation: 01 Item/Group: 001A Hazard: EXPLOSION

T.C.A. 50-3-105(1): The employer did not furnish employment and a place of employment which were free from recognized hazards that were causing or likely to cause death or serious physical harm to employees: In that, the employer did not ensure carbon disulfide vapor-in-air concentrations exiting a storage tank were controlled and carbon disulfide vapor-in-air concentrations in areas containing the storage tank cleaning process were maintained to less than the respective lower flammable limit, which exposed employees to both toxic and explosive environments. Employees, in the process of cleaning a storage tank located at 100 Spontex Drive, Columbia, TN, delivered approximately 6500-psi of water pressure to the tank interior, purposefully dislodging rust and scale build-up and consequently releasing carbon disulfide liquid and corresponding vapor. The concentration of carbon disulfide existing in the tank interior or directly outside the tank was never measured; however an ignition source caused an explosion and resultant flames discharged from the tank manhole for several seconds. The occurrence of an explosion indicated that a minimum carbon disulfide vapor-to-air concentration of 1 , or 10,000-ppm, found an ignition source. An employee was exposed to the flash fire, which caused the employee's death. Consensus standards, such as NFPA and API, detail precautions and procedures for controlling flammable atmospheres during storage tank cleaning. A feasible abatement method to correct this hazard, as described in NFPA 326 and API 2016, is to remove flammable vapors from the tank prior to cleaning, and thereafter ensure by means of continuous or periodic monitoring a carbon disulfide vapor-in-air mixture does not exceed a predetermined vapor-in-air mixture (e.g., 10of the lower flammable limit). Procedures should also be developed and implemented to cease cleaning activities if the predetermined vapor-in-air mixture limit is reached, and subsequently eliminate or control the source of vapors. Abatement Verification Required