Sun Pacific Lerdo Highway Cold Storage facility - Executive Summary |
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EXECUTIVE SUMMARY Accidental Release Prevention and Emergency Response Policies Sun Pacific utilizes anhydrous ammonia in the refrigeration system at their cold storage facility east of Shafter, California. It is Sun Pacifics policy to comply with all applicable governmental regulations. Further, it is Sun Pacifics objective to be a responsible citizen of the community in all of its business activities. Sun Pacific emphasizes safe and environmentally sound operating practices and procedures through their employee training programs. In addition to job specific training, operators and maintenance personnel receive training in accident prevention, safety, and first aid. Additionally, an emergency action plan has been prepared for Sun Pacific and a chain of command to respond to emergencies has been established. Sun Pacific has developed a detailed Compliance Audit Checklist which is used to evaluate compliance with the Process Safety Management (PSM) and 40 CFR Part 68 (RMP regulations). At least every three years, Sun Pacific audits these programs and any findings of noncompliance are documented and responded to and the deficiencies are corrected. Description of the Stationary Source and Regulated Substances Sun Pacific owns and operates a cold storage facility located at 33374 Lerdo Highway. Shafter is the closest city to the Sun Pacific Lerdo Highway Cold Storage facility. The plant was constructed in 1988. The refrigeration system has been upgraded several times, with the last expansion completed prior to September 1, 1992. At Sun Pacific, anhydrous ammonia is used in the refrigeration system which provides process cooling for the cold storage facility. The system consists of a high pressure receiver, six evaporative condensers, four compressors, three recirculation accumulators, and numerous evaporators. The three recirculation accumulators and evaporator units provide cooling to the cold storage rooms and the pre-cool/de greening rooms. Flooded evaporators are utilized in the degreening room. The halls and truck dock areas are cooled by direct expansion evaporators. During normal operation, the anhydrous ammonia is distributed throughout the refrigeration system. However, during major maintenance activities, the entire refrigeration system can be pumped down to evacuate the ammonia from the system and store it in the high pressure receiver. The maximum quantity of ammonia that can be stored in the high pressure receiver is 20,987 pounds. For purposes of the offsite consequence analyses, the RMP regulations define the toxic endpoint for anhydrous ammonia as 0.14 mg/l (200 ppm). This concentration has been established by the American Industrial Hygiene Association as the Emergency Response Planning Guideline Level 2 (ERPG-2). ERPG-2 is the maximum airborne concentration below which it is believed that nearly all individuals could be exposed for up to one hour without experiencin g or developing irreversible or other serious health effects or symptoms which could impair an individuals ability to take protective action. Worst-Case Release Scenario and Alternative Release Scenario Offsite consequence analyses are used as tools to assist in emergency response planning. The RMP regulations require the owner or operator of a stationary source to analyze the offsite impacts due to an accidental release of a regulated substance. The offsite consequence analysis for a Program 3 process must analyze the worst-case release scenario and an alternative release scenario. Since Sun Pacifics ammonia-based refrigeration system is considered a Program 3 process, both release scenarios were evaluated in the offsite consequence analysis. The offsite consequence analysis must include an estimate of the residential population within an area potentially affected by the accidental release scenario. This area is defined as a circle with a radius equivalent to the d istance the release would travel with concentrations at or above the endpoint. The circle also defines the area in which potential environmental receptors must be identified. The worst case release is defined by the U.S. EPA as the total release of the contents of the single largest vessel or pipe within 10 minutes. For liquefied gases stored under pressure, the entire contents of the vessel or pipe are assumed to be released as a vapor. A total vapor release is highly unlikely. However, this standardized worst case scenario was developed for emergency response agencies to use for planning purposes. An alternative release scenario is a release that is more likely to occur than the worst-case release scenario. For Sun Pacific, the alternative release scenario was selected based on the results of the Process Hazard Analysis (PHA) for the ammonia-based refrigeration system. A credible release event with a high discharge rate would potentially have the greatest offsite impact. A failure of one of the pump seals was identified in the PHA as having a medium probability of occurrence with a possible high discharge rate, and therefore, was chosen as the alternative release scenario. Sun Pacific has analyzed the offsite consequences of the worst-case and alternative release scenarios. For the worst-case release scenario, the release of 21,000 lbs. of ammonia over a 10 minutes period within the engine room, the plume would travel 1.2 miles at concentrations at or above the endpoint. Using 1990 Census data, the population potentially affected within the worst-case release scenario circle is 48 persons. There were no sensitive receptors or environmental receptors within the worst case release scenario circle. In the alternative release scenario, a failure of the pump seal was modeled as a release of liquefied ammonia stored under pressure. For a release of 580 lb/min of anhydrous ammonia within the engine room, the model calculated tha t the plume would travel 0.1 mile at concentrations at or above the endpoint. No residences are located within the 0.1 mile area around the Sun Pacific facility. As such, there would be no population impacts from the alternative release scenario. There were also no sensitive receptors or environmental receptors within the alternative release scenario circle. The ammonia refrigeration equipment, except for the evaporative condensers, is located within a building, which would greatly reduce the impact of a release. The modeling performed as part of this offsite consequence analysis includes a mitigation factor which assumes that the release is within an enclosed space, in direct contact with the outside air. General Accidental Release Prevention Program and Chemical-Specific Prevention Steps A PSM program, which meets the requirements of the general accidental release prevention program, has been developed at Sun Pacific to address the anhydrous ammonia system. The P SM program includes the following chemical- specific prevention steps: Written process safety information, including information pertaining to the hazards of ammonia, the technology of the process, and the equipment in the process has been compiled. An initial Process Hazard Analysis (PHA) was performed and will be updated and revalidated at least every five years. Written operating procedures have been developed and implemented, and are reviewed at least annually. Safe work practices, such as lockout/tagout, confined space entry, opening process equipment or piping, and control over entrance into the facility have been developed and implemented. Each employee involved in operating the ammonia system has received initial training and refresher training at least every three years. Written mechanical integrity procedures have been established and implemented. A Management of Change (MOC) program has been developed and implemented to address all proposed chan ges to the ammonia system. Pre-startup safety reviews are performed when a modification is made to the ammonia system that is significant enough to require a change in the process safety information. Audits are conducted at least every three years to evaluate compliance with the CalARP regulations. Incident investigation procedures have been established. A written plan of action regarding the implementation of employee participation has been developed and implemented. Hot work permits are issued for all hot work operations conducted on or near the ammonia system. A Contractor Safety Policy has been developed and implemented. To ensure that the general accidental release prevention program and the chemical-specific prevention steps are implemented, Sun Pacific has assigned overall responsibility for the RMP elements to the General Manager. The General Manager has the overall responsibility for the development, implementation, and integration of the RMP eleme nts. Five-Year Accident History Sun Pacific has not had any accidental releases from the ammonia-based refrigeration system that have resulted in deaths, injuries, or significant property damage on site, or known offsite deaths, injuries, evacuations, sheltering in place, property damage, or environmental damage in the last five years. Emergency Response Program Sun Pacific has established an emergency action plan and a chain of command to respond to emergencies and to notify emergency responders when there is a need for a response. However, an emergency response program does not need to be developed for the facility since Sun Pacific employees will not respond to accidental releases of ammonia, the facility is included in the community emergency response plan, and appropriate mechanisms are in place to notify emergency responders. Planned Changes To Improve Safety Based on the PHAs performed in October, 1998, the following changes were recommended and will be impleme nted by December, 1999. 1) Installation of ammonia detectors in the engine room and key process areas. 2) Installation of an actuator on the 4 inch suction ball valve so that the pump can be isolated from the accumulator with a remote switch outside of the accumulator room in the event of a seal failure (i.e. motor operated valve for isolation). 3) Consider installation of PSV between block valve and solenoid valve on liquid line associated with accumulator #3. Through the accidental release prevention program, Sun Pacific regularly evaluates the need for any changes to improve safety. Currently, Sun Pacific does not have any additional changes planned to improve safety other than the above listed items. |