Spontex, Inc. - Executive Summary |
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Spontex, Inc. is a sponge manufacturer located near Columbia, Tennessee in Maury County. Spontex utilizes carbon disulfide (CS2) as process chemical in a viscose production process. CS2 is shipped to Columbia, Tennessee by way of rail cars. Spontex utilizes nitrogen to displace the CS2 and unload it from a rail car to two 10,500-gallon tanks. The storage tanks are surrounded by a water-filled moat, which provides secondary containment. From the holding tanks, CS2 is pumped to a 55-gallon "measuring pot" on an as needed basis, and then gravity fed to the viscose process. The offsite consequence analysis considers two carbon disulfide release scenarios: the "worst case" and "alternate release" scenarios. For the worst analysis, EPA states that the owner or operator shall assume the maximum quantity in the largest vessel is released as a gas over a ten-minute period due to an unspecified failure. Further, EPA mandates in the rule that the following meteorological conditions be assumed in the worst case analysis: wind speed of 1.5 meters per second, highly daily temperature of 116 degrees Fahrenheit, an average humidity of 65%, and a stability class of F. The alternative scenario is defined as "more likely to occur than the worst case scenario". Dispersion modeling was performed to determine the distance traveled by the carbon disulfide before its concentration decrease to the toxic endpoint of 0.16 mg/L or 16 ppm as defined in Part 68 Appendix A. This is defined by the American Industrial Hygiene Association (AIGH) as the "maximum airborne concentration below which it is believed that nearly all individuals could be exposed up to one hour without experiencing or developing irreversible or other serious health effects or symptoms which could impair an individual's ability to take protective action". For Spontex, the worst case scenario involves the failure of storage tank containing 10,500-gallons of carbon disulfide. The offsite consequence analysis for this scenario w as performed for two sets of conditions. The first set followed conditions pre-defined by EPA, a release of the entire contents, from a single vessel in ten minutes. The analysis will include the toxic endpoint and the considerations of the populations residing within a full circle with the radius corresponding to the toxic endpoint distance. EPA set these conditions to facilitate the performance of the offsite consequence analysis. However, some assumptions must be addressed about carbon disulfide; First CS2 has a flash point of -22 F. The explosive window is between 10,000-500,000 ppm. Vapors are heavier than air and can travel considerable distances to find ignition sources. Next, CS2 is sensitive to static discharge because of its low conductivity, flow or agitation can cause electrostatic charges, which can spark and catch fire, causing substances to be formed such as sulfur dioxide and carbon monoxide. CS2 vapor concentration of 500 ppm is immediately dangerous to life and health (IDLH). Only population downwind of the release is potentially affected. The dispersion modeling for both worst case and alternate release was performed using RMP*Comp which is available on the EPA web page. The worst case scenario has an estimated radius of 1.8 miles and an estimated residential population of 5,000 people. For the alternate release scenario, the distance to toxic endpoint was 0.4 miles with an estimated residential population of 100 people. Spotex, Inc is in compliance with the OSHA PSM rule and the EPA RMP rule. Key components to the prevention program are: high level training for plant operators, preventative maintenance program, technological process and safety equipment, effective operating procedures, performance of hazard review, and frequent inspection programs. No accidental releases have occurred in the last five- (5) years. The facility has an emergency response program, which has been coordinated with the fire and police departments of Maury County. The pr ogram includes as emergency notification plan and names the facility official that will be incident commander. Emergency response drills and drill evacuations are conducted every year followed by a drill critique of all involved. Planned changes to improve safety include keeping the PSM team active and conducting an HAZOP analysis when process or equipment is changed. |