DEL MAR COLD STORAGE - Executive Summary

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Del Mar Foods operates a processing and storage facility in Watsonville, CA.  Anhydrous ammonia is the refrigerant used for produce processing and storage.  Risk prevention and emergency response procedures are in place at this facility.  An Emergency Response Plan is maintained at the facility and lists the responsible personnel and the policies for responding to an accident involving the regulated substance. 
There are five separate refrigeration systems at different facility production and freezer storage areas.  Operators are present to monitor the systems supporting production lines whenever they are in operation.  The freezer storage operates 24 hours per day and has safeties and operator alarming capacity.  An operator is on call 24 hours per day.  There is a list of responders experienced with ammonia refrigeration that would respond and determine specific responses for any incident. 
 Safeties and detection equipment is tested and maintained by experienced maintenance personnel as spelled out in the SOPs and the maintenance program. 
Age and condition of equipment various considerably as systems were added over the years.  The oldest system is approximately 40 years old and the newest, 5 years.  Total facility charge is approximately 30,000 LBS. 
Both a worse case and an alternate release scenario were modeled for this RMP utilizing a computer modeling program.  The worse case was an release of the entire ammonia charge of the largest system in 10 minutes with ambient conditions as required by EPA regulations.  The alternate was a release for 17 minutes averaging approximately 105 LBS/minute.  This is a more probable release due to items such as rotating seals, pressure relief valves, leaks in piping, charging system or draining oil.  The modeling software used was "A Real Locations Of Hazardous Atmospheres" (ALOHA) from the National Safety C 
ouncil in cooperation with the EPA.  Both scenarios were considered releases in a rural setting.  Release plumes were plotted on maps which showed the location of populations, schools,  public areas, and acute care facilities if effected by the release.  The mapping software utilized was "Mapping Application for Response and Planning of Local Operational Tasks" (MARPLOT) also from the National Security Council.  Effected populations were estimated using "Land View III", a computer census modeling program from the Bureau of Census that is able to calculate census data of areas defined on MARPLOT generated maps. 
Offsite consequences were analyzed at 200 PPM  level of concern for the two above release scenarios.  Results show the worse case scenario having a potential endpoint of 2.1 miles.  If the area was encircled with the 2.1 mile endpoint distance as the radius, the total area population would be approximately 600.  In this area are schools, public parks and commercial/ industrial t 
ype businesses.  The alternate scenario has considerably less offsite consequence with an endpoint of 1,572 feet at 200 PPM.  Some residences and nearby industrial/commercial businesses would be effected. 
There are various measures in place or recommended as risk reduction in the Process Hazard Analysis (PHA)  to limit the endpoint distance of a release.  Two of the systems have emergency control boxes for manual pressure relief.  Adding ammonia detection is a PHA recommendation.  Preventive maintenance and safety inspections are used to insure equipment and piping is maintained and operating in a safe manner.   
Del Mar Storage maintains a release prevention program to eliminate or minimize releases.  The program includes regular inspections, monitoring equipment and logging conditions, scheduled maintenance, and operator training.  Releases are documented and analyzed for ways to prevent a similar future release.  A Risk Management Program whic 
h includes accident prevention procedures for the ammonia refrigeration system is maintained onsite.  
The ammonia refrigeration system has specific safety procedures to prevent a release.  Operators and mechanics are trained for safe operation and maintenance of the refrigeration system.  They are also trained in emergency response procedures in the event of an ammonia release.  There are emergency shut off switches outside the mechanical rooms for shutting down the systems. Two of the five systems have emergency control boxes and diffuser systems which allows system pressure to be relieved manually.   
There has been one reportable release in the last five years.  The release was due to human error resulting in a pressure relief valve releasing vapor.  Approximately 2,000 pounds of ammonia was released over a 45 minute period.  The release was outdoors during a night cleanup shift.  There were no injuries or property damage.  The Watsonville Fire Depart 
ment responded. 
In event of a release, certain personnel are designated to determine the potential hazard and coordinate response procedures.  The emergency coordinator is responsible for contacting emergency response agencies, schools, daycare centers, and acute care facilities that may be effected by the release.  The coordinator will also be responsible for evacuation of employees if necessary, and for coordination with community emergency responders if offsite evacuations are required.   
Specific recommendations and time frames resulting from the PHA are listed as part of the Risk Management Programmaintained onsite.  The piping and support systems of the older refrigeration systems need to be upgraded.  Piping and vessels showing signs of corrosion needed to be inspected and tested by a qualified testing agency and replaced if necessary.  Alarm and detection systems also need upgrading.  Operating, maintenance, 
training and safety procedures will be formalized with improved written documentation.
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