Diatec Environmental Company - Batavia - Executive Summary |
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1.0 SOURCE AND PROCESS DESCRIPTION 1.1 SOURCE The Diatec Environmental facility in Batavia, Illinois, is subject to the United Stated Environmental Protection Agency's (USEPA's) Risk Management Program (RMP) for Accidental Chemical Release regulation (40 Code of Federal Regulations [CFR] 68) because it has two interconnected storage tanks that contain greater than the threshold quantity (10,000 pounds) of dimethylamine (DMA) (Chemical Abstract System [CAS] Number 124-40-3) . The DMA used at the facility is a 65 percent, by weight, solution in water. The DMA handling system consists, primarily, of two storage tanks and delivery piping. The storage tanks, when both are full, can contain 77,000 pounds of the DMA solution, which includes 50,000 pounds of DMA. The DMA is used as a raw material for the Mannich production process. 1.2 PROCESS DESCRIPTION The DMA handling process consists of two outdoor storage tanks, located one above the other within a secondary containment dike on the south side of the property. The DMA solution is received from tank trucks which fill the bottom tank and then place the balance of the delivery into the top tank. A new load of DMA is ordered only when there is enough storage capacity available to handle a full load. Within the storage tanks, the DMA solution is a liquid at approximately 25 psig. During the Mannich production process, DMA solution is pumped from the storage tanks, through the distribution piping to the blending unit. The DMA solution is pre-mixed with formaldehyde solution and passed through a heat exchanger to remove the heat of mixing generated before being mixed with the acrylamide backbone. The DMA and formaldehyde react very quickly with the acrylamide to form the Mannich product, which is transferred to holding tank to await packaging There are multiple safety system protecting the DMA handling system. The storage tanks were tested in 1996 and were found to meet the testing requirements of the Department of Transportation (DOT) for portable tank equipment, which exceed the permanent storage tank design requirements typically specified by the American Petroleum Institute (API). The tanks are also protected from overpressure by safety relief valves which will prevent hazardous pressure levels from developing within the tanks 2.0 POTENTIAL RELEASE SCENARIOS Consistent with the RMP rule requirements, two specifically defined release scenarios (a worst-case and alternative-case release) were analyzed for the DMA handling process to determine the maximum distance, or flammable endpoint, where a release of DMA could have off-site consequences. The potential results of these scenarios are described in Sections 2.1 and 2.2. The worst-case distance is defined as the point at which an explosion of the vapor cloud will degrade to an overpressure of 1 pound per square inch (psi). The alternative-case endpoint is defined as the distance where the concentration of DMA is no longer within the fl ammable range (i.e., below the lower flammability limit). These distances represent the points at which nearly all individuals will not be permanently affected by exposure. 2.1 WORST-CASE RELEASE For the worst-case release, the facility must assume that the entire contents of both DMA storage tanks are released, a vapor cloud forms, and a detonation occurs. The distance to the endpoint is defined as the distance an explosion from an accidental release will travel before dissipating to the point that serious injuries from short-term exposures will no longer occur. For DMA, the endpoint is an overpressure of 1 psi (at 1 psi, windows will break). Applying the TNT equivalency equation1 to a worst-case release from the interconnected vessels gives an endpoint distance of 1,450 feet (0.28 miles).Although the worst-case consequence analysis is required by the RMP, it should be considered a highly unlikely event. Design, construction, and operation of the DMA storage tanks are such th at catastrophic failure is extremely remote. The storage tanks were designed and constructed in strict accordance with the DOT and IMCO Sea Shipping Container requirements. The worst-case release scenario is unlikely for the following additional reasons: The storage tanks are each equipped with two safety relief valves (SRVs) set to relieve internal pressure at 31 psig. A high pressure excursion would not occur as long as the SRVs continued to function. The facility has a preventive maintenance program in place to maintain the ongoing integrity of the tanks. The area is fenced and locked to prevent tampering. The appearance of the external surface of the storage tanks is visually inspected regularly, while the process is operation, for any departures from normal. The findings are recorded in the plant log and repair(s) arranged when necessary. DMA solution is not corrosive to the stainless steel material of construction of the storage tanks, and the facility inspects the tanks for external corrosion. The vessel is guarded against inadvertent contact with vehicular traffic by the walls of the secondary containment dike. 2.2 ALTERNATIVE-CASE RELEASE The alternative scenario is considered to be defined by a release of DMA that is "more likely" to occur than the worst-case scenario and reaches an endpoint off site. The alternative scenario chosen for analysis involves the release of DMA if the transfer hose were to become disconnected for one minute during tank truck unloading. The assumption is that the DMA in the solution would evaporate and that the vapor cloud formed would reach an ignition point causing the DMA to burn (not explode). The endpoint distance for this occurrence is defined as the distance at which the vapor cloud is no longer within the flammable range (i.e., below the lower flammability limit (LFL)). For the Diatec facility, the release rate for the DMA evaporating from the spilled pool of DMA solution would be 90 lbs./min. resulting in a distance to the LFL of less than 0.1 mile (528 feet). The alternative-case scenario is also considered very unlikely due to the following reasons: The tank truck unloading process is under constant supervision of both a plant operator and the delivery truck driver. The facility has a well-documented training program for process operations. 3.0 PREVENTION PROGRAM The facility has carefully considered the potential for accidental releases of hazardous chemicals including DMA, such as the occurrence of the worst-case and alternative-release scenarios described in Section 2.0. To help minimize the probability and severity of an ammonia release, a prevention program that satisfies the Occupational Safety and Health Administration, Process Safety Management of Highly Hazardous Chemicals standard (29 CFR 1910.119) has been implemented. The key components of the prevention program are summarized below: Critical process safety information has been developed and documented regarding the chemical hazards, the design basis of the processes, and the equipment. This information is available to the operators and used to fully understand and safely operate the production processes. An employee participation program, which includes employees from all levels of the organization and from all areas within the plant (i.e., production and maintenance) has been developed. The employees that operate the processes are the most knowledgeable and are best able to easily, effectively, and regularly recommend changes or improvements which enhance safety. A formal process hazard analysis (PHA) was performed using the HAZOP technique. A team with expertise in engineering, operations, maintenance, and safety evaluated the existing processes in depth and developed recommendations to improve the safety and operability of the system. The PHA addressed: (1) process hazards, (2) previous incidents, (3) engineering and administrative controls applicable to the hazards, (4) the conseq uence of control failure, (5) facility siting, (6) human factors, and (7) a qualitative evaluation of possible safety and health effects of control system failures. The PHA resulted in multiple procedural and/or hardware recommendations to improve the safety and operation of the system. These recommendations are in the process of being resolved and many changes have already been implemented. The PHA will be updated and revalidated every five years. Written operating procedures (OPs) have been prepared to provide the basis for proper and safe operation of the processes. The OPs include procedures for normal operation, startup, shutdown, emergency operation, and emergency shutdown. They also describe safe operating limits for temperature and pressure, the consequences of operating outside these safe operating limits, and a description of safety systems and how they operate. Process operators receive initial hands-on operations training from an experienced operator and safety meeti ngs are held once a quarter. The training content is based upon the process safety information and operating procedures. The training program ensures that the operators understand the nature and causes of problems arising from system operations and serves to increase awareness with respect to the hazards particular to DMA. Formal authorization systems (i.e., management of change procedure, pre-startup safety review) are in place to ensure that system changes or expansions are as safe as the original design and that an independent recheck, prior to start-up, confirms that the changes are consistent with the engineering design and safety requirements. Events that might (or did) cause an accidental or unexpected release of DMA, or any other hazardous chemical, are subjected to a formal investigation. The objective of the investigation is to determine why the incident happened and to correct any deficiencies in such a way as to prevent recurrence. Contractors that are hired to work any equipment used in a process that involves a hazardous chemical are "pre-qualified" based upon their knowledge of the chemical hazards, understanding of applicable codes and standards, and their demonstrated ability to work safely. Management must approve any hot work (i.e., spark or flame producing operations such as welding, cutting, brazing, and grinding), by executing a written hot work authorization permit to verify that appropriate precautions to prevent fire have been implemented prior to the performance of such work. Periodic inspections are performed for major equipment, including heat exchangers, pumps, and piping. Adherence to fire codes and preparation for fires, storms, or events which could impact the facility's processes. Planning with the local fire department to ensure a rapid response to potential incidents involving the facility's processes or external events, such as tornadoes. Prevention program compliance audits performed every 3 years to verify that th e elements are being properly implemented. Any deficiency found in an audit is corrected. 4.0 ACCIDENT HISTORY There have been no accidental releases of DMA at the facility in the last 5 years (since June 1994) that have resulted in on-site death, injury, or significant property damage or off-site death, injury, evacuation, sheltering-in-place, property damage, or environmental damage. 5.0 EMERGENCY ACTION PROGRAM The facility has implemented a written Emergency Action Plan (EAP). The EAP is intended to address all emergencies at the facility in addition to incidents related to a minor release of DMA. The EAP includes awareness and response training for employees, coordination with the local fire department, and evacuation of the facility. The plan references procedures that details what personal protective equipment and spill response equipment is available for a response to a spill or leak of the hazardous chemicals used at the facility. 1 This equation is presented in the Unit ed States Environmental Protection Agency (USEPA) Risk Management Program Guidance for Offsite Consequence Analysis (OCA), dated April 1999, and serves as the basis for determining the endpoint distance for a release of a flammable liquid or gas. DRAFT ENVIRONMENTAL RESOURCES MANAGEMENT 3 RMP FOR DIMETHYLAMINEEXECUTIVE SUMMARY AND DATA ELEMENTSDIATEC ENVIRONMENTAL COMPANYf:\cpf\ciba\99188nc\wp\rpts\execsum1.doc |