Cebro Frozen Foods - Executive Summary

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Anhydrous Ammonia Refrigeration System 
June 1999 
Cebro Frozen Foods (Cebro) prepared a chemical risk management program (RMP) in general accordance with California Code of Regulations, Title 19, Section 2735.1, et. Seq.  The regulations are also referred to as the California Accidental Release Prevention (CalARP) program.  The Federal Environmental Protection Agency (EPA) also regulates facilities with certain toxic and flammable substances.  The federal regulations are codified in Title 40 of the Code of Federal Regulations (CFR), part 68. 
Cebro prepared the RMP program to satisfy regulatory requirements and to demonstrate a commitment to evaluate and improve anhydrous ammonia handling systems and practices at the facility. Cebro has incorporated many state-of-the-art safety features into the ammonia refrigeration system at the facility as part of the original system construction.  In the unlikely event that 
a chemical release does occur at the facility, Cebro personnel are trained in the appropriate response measures, relying on emergency services provided by the local fire department and the Stanislaus County Hazardous Materials Response team.  Cebro will continue to improve ammonia-handling safety through the implementation of the prevention program elements of the RMP program. 
Cebro is located at 2100 Orestimba Road in Newman, California.  The area is zoned for agricultural and industrial use.  The facility is approximately 2 miles west of Highway 33, which runs north and south through Newman.  Cebro is a family owned business that produces frozen vegetables.  Cebro constructed the facility in 1993 with all new refrigeration system components.  
Anhydrous ammonia is used in a refrigeration system at the facility.  The ammonia refrigeration system, which is a closed system, contains approximately 17,000 pounds of anhydrous ammonia. The system provides cooling to the cold storage rooms 
, a quick freezer, and a plate chiller.  The cold rooms are used to store fresh and frozen vegetables.  The quick freezer is used for the initial vegetables freezing.  The plate chiller provides cold water for cleaning and cooling the fresh vegetables.  
The RMP regulations require facilities to identify and evaluate chemical release scenarios resulting from potential failures of the chemical handling systems covered by RMP.  Program 3 requirements of the RMP apply to the Cebro facility due to the quantity of ammonia used.  Program 3 facilities are required to evaluate a worst-case release scenario (release parameters are defined by the regulations) and an alternative release scenario.  A worst-case release scenario is defined in the regulations as "the greatest amount held in a single vesselreleased as a gas over 10 minutes."  An alternative release scenario is identified as a release that is more likely to occur at the facility. 
The largest ammonia vessel at Cebro, the high-pressu 
re receiver, has a maximum capacity of 18,280 pounds of ammonia. The estimated maximum quantity of ammonia used in the system is only 17,000 pounds, therefore, the worst-case release scenario for the facility is a release of 17,000 pounds of ammonia in 10 minutes.  Catastrophic failure of the high-pressure receiver would be required for this scenario to occur.  As required by the RMP regulations, pessimistic atmospheric conditions, very conservative chemical dispersion characteristics, and a toxic endpoint of 200 parts per million (ppm) ammonia vapor were assumed.  The predicted distance to the toxic endpoint for the worst case release scenario is 2.36 miles.  Table 2-1 of EPA's Model Risk Management Program and Plan for Ammonia Refrigeration, November 1998, was used for the chemical dispersion analysis.  No administrative controls or mitigation measures were considered in the analysis. 
The alternative release scenario described in the above referenced EPA document was used by Cebro.  
The release scenario is described as a <-inch effective diameter orifice leaking liquid ammonia and resulting in an airborne release, representative of a pipe connection leak or a gasket rupture.  The evaluation used a release rate of 100 pounds/minute and average weather conditions.  The predicted distance to the toxic endpoint is 1,056 feet.   
The RMP regulations require a review of the accidental release prevention program and chemical specific prevention steps used by the facility.  Cebro has incorporated many safety features in the ammonia refrigeration system to prevent system failures and to mitigate potential releases.  The predominant safety concern with closed-loop ammonia systems is an inadvertent buildup of pressure exceeding pressure ratings or capacities of equipment due to ammonia expansion.  The Cebro ammonia system is continuously monitored by automated control systems that shut down components if deviations from normal operating conditions occur.  Further, the syste 
m is equipped with pressure relief valves on all pressure vessels and most, if not all, additional locations within the ammonia system where ammonia could become trapped. 
Other safety features at the facility include:  
7 emergency shutdown systems 
7 component specific safety shutdowns 
7 an ammonia leak detection system in all process areas that contain ammonia equipment 
7 an ammonia fire dump system that can be used to relieve pressure in vessels 
7 ammonia pipes are color-coded 
7 all ammonia related computer systems are Y2K compliant 
In addition to the physical features of the ammonia refrigeration system at the facility, Cebro has extensive administrative controls in place to maintain safe operation of the system.  Administrative controls include, but are not limited to: formal training programs for system operators and mechanics, emergency training, a hot work permit program, a lock-out/tag-out program, a contractor safety program, incident investigation program, mechanical integri 
ty program, management of change program, pre start-up safety review program and an RMP/PSM auditing and inspection program. Written standard operating procedures (SOPs) have been prepared for the ammonia system at the facility.  The SOPs will provide a basis for site specific operator training and a ready reference for operating and trouble-shooting the systems. 
Cebro is committed to maintaining the mechanical integrity of the ammonia refrigeration system.  A preventive maintenance system is utilized to manage the maintenance of the refrigeration system.  Preventive maintenance at the facility includes shift, daily, weekly, and periodic inspection; calibration; testing; and overhaul of ammonia system equipment.  The system is used to track equipment performance and to create reports that are used by maintenance personnel to monitor the frequency of repairs and deviations from normal operating parameters. 
The RMP regulations require a review of the five-year accident history at the  
regulated facility.  The Cebro facility at 2100 Orestimba Road reported no accidental release of ammonia during the past five years. 
Changes to improve safety at the facility are ongoing.  Many of the mitigation measures suggested by the process hazard analysis team have already been implemented.  Others will be implemented during the next several months.  The status of significant mitigation measures is as follows: 
7 The review of SOPs is nearly completed 
7 Valve tagging is completed 
7 Security fencing of the compressor and ammonia vessel pad area is completed 
7 Spring return valves are now used for all oil draining 
7 Preventive maintenance and inspection recommendations have been implemented 
7 Catwalks and guard rails for inspection and maintenance of condensers have been installed 
7 Cebro will be installing roof access ladders 
7 Cebro has developed coil cleaning procedures 
Cebro will respond to all suggested mitigation measures promptly.  Schedules of proposed actions have been es 
tablished by Cebro.  Management responses and support will be consistent with Cebro's commitment to safe and environmentally responsible operations.
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