Hunt Wesson Inc. - Executive Summary
This Facility is a food processing plant that runs continuously. The regulated substances under the RMP
rule are anhydrous ammonia (CAS #7664-41-7) and propane (CAS #74-98-6). Ammonia is used as a primary refrigerant for cooling purposes in both production and storage areas. There are two separate refrigeration systems on site operating independent of one another. Both systems are a closed loop with normal operating pressures of less than 200 PSI. The main plant system (process) has a maximum charge of 19,000 lbs, of ammonia contained throughout it. The Hassia system (process) has a maximum charge of 14,050 lbs, of ammonia contained throughout it. The remaining 1,450 lbs, are stored outdoors in ten 145 lb D.O.T. certified blue cylinders. Propane is used for fuel for industrial lift trucks and as an alternative fuel in the event that the plant (Hunt Wesson) is curtailed by Northern States Power Company due to severe cold weather, fuel shortages or line work. The propane sto
rage vessel is outdoors at ambient temperature.
Maximum quantities on-site for each regulated substance are
Ammonia (Anhydrous)-34,500 lbs.
Worst-case scenario for a toxic substance:
The worst-case release toxic endpoint was determined using EPAs "RMP Guidance for Ammonia Refrigeration" Reference tables or equations. This scenario was based on the following criteria.
Vessel: High Pressure Receiver (HPR) 3ft X 17.5 ft.
Amount released: 5,000 lbs
Duration of release: 10 minutes
Release rate: 500 lbs/ min
Wind speed: 1.5 meter/sec
Atmospheric stability: F
Referencing the tables in the "RMP Guidance for Ammonia Refrigeration", the toxic endpoint for this scenario is 0.90 miles. Within the affected area is a population of 2,638 people, one school, two recreational areas, commerci
al facilities and residential areas. This information was obtained by using "Landview" census data. The released amount was calculated on the HPR being outdoors at full capacity and there were no mitigation factors considered.
Alternative Release Scenario for a toxic substance:
The alternative release toxic endpoint was determined using the EPAs "RMP Guidance for Ammonia Refrigeration" reference tables or equations. The scenario was based on the following criteria.
Scenario: Relief valve failure on the HPR.
Orifice size: 1/2".
Release Rate: 400 lbs/min.
Duration of release 10 min.
Amount released 4,000 lbs.
Wind speed 3.0 meter/sec.
Atmospheric stability D.
Referencing the tables in the "RMP Guidance for Ammonia Refrigeration", the toxic endpoint for this sc
enario is 0.20 miles. The population within this area is 40 people. Also affected are several businesses and residences. Although considered a more likely scenario, there are many safeguards that are in place, at this facility to minimize the occurrence of such a release (see General Accidental Release Prevention Program of this Summary).
Accidental Release and Emergency Policies:
Hunt Wesson Inc. has established an in-house level A emergency response "HAZMAT" team to quickly respond to and handle releases of Anhydrous Ammonia. The established steps include initial training under the OSHA regulation 29 CFR 1910.120 "HAZWOPER". The facility has also established annual retraining for all personnel that are on the HAZMAT Team as well as periodic spill drills and plant wide evacuation drills to assure all employees are prepared in the event of an emergency. Hunt Wesson Inc. has also established training with the Fire Department personnel and community Local Emergency Planning Commi
ttee. These established plans and procedures shall be periodically reviewed to assure that they are current and up to date.
General Accidental Release Prevention Program and Chemical Specific Prevention Steps:
Within the last five years there has not been an accidental release that caused offsite impacts.
Hunt Wesson Inc, has not only complied with the EPA Risk Management Program but also the OSHA Process Safety Management regulations CFR 1910.119 & 1910.120 to assure that the Ammonia Refrigeration System is well maintained and employees are properly trained and periodically retrained to assure they are kept up to date on any changes and new operations that may effect them. In addition, to maintain the mechanical integrity and safety of this process. The ammonia compressors automatically shut down if the pressure exceeds 200 PSI. The relief valves are preset at 250 PSI. Hunt Wesson Inc. practices the following industry codes and standards.
ASME Boiler & Pressure Valve Codes.
31.1 & B31.5 Piping Codes.
IIAR industry guideline for safety and good engineering practices.
NFPA guidelines for fire protection equipment.
Through regular audits, training, maintenance, testing, and inspection programs the ammonia refrigeration system at Hunt Wesson Inc. has established a history of safe operation and that community emergency action plans are current and training with community services is done for a safe response in the event of an accidental release.
Emergency Response Program:
Primary Public Emergency Responders:
City Fire Department:
County Hazardous Material Response Team:
City Law Enforcement:
County Sheriffs Department:
City and County Ambulance Service:
Dunn County LEPC
Special Resources Available from Facility:
Hunt Wesson Inc. has trained the refrigeration operators, maintenance technicians and selected production and office personnel in Hazardous Waste Operation and Emergency Response '29 CFR 1910.120'. The trained personnel will assess each release s
ituation and determine the appropriate emergency response to initiate. This could be by simply tightening a packing nut or flange bolt or initiating a system shut down. This facility has also established written operating procedures for the ammonia refrigeration system and have included in those procedures the Emergency Shutdown and isolation in the event of a release. Hunt Wesson Inc. has purchased Level A Chemical Suits, Self-Contained Breathing Apparatus and other appropriate equipment to support the in-house level A HAZMAT team. This team will coordinate their efforts with the outside emergency services to assure the safety of all.