Chief Wenatchee-Malott - Executive Summary
A. Accidental Release Prevention and Emergency Response |
Chief Wenatchee, Inc. - Malott facility (hereafter referred to as Chief Wenatchee-Malott) accidental release prevention policy involves a unified approach that integrates technologies, procedures, and management practices. It is the policy of Chief Wenatchee-Malott to adhere to all applicable federal and state safety and environmental regulations.
Chief Wenatchee-Malott's personnel do not respond to ammonia releases. The emergency plan requires employees to call 9-1-1 and evacuate the plant in the event of an ammonia release.
At Chief Wenatchee-Malott anhydrous ammonia is used on-site. Ammonia is considered hazardous by EPA and is listed on the Extremely Hazardous Substance (EHS) list. Chemical properties of ammonia make it necessary to observe certain safety precautions in handling ammonia in order to:
7 Prevent unnecessary human exposure
7 Reduce the threat to our personnel
7 Reduce the threat to the community
ty and Regulated Substance Handled
Chief Wenatchee-Malott is a fruit processing and cold storage facility, located at 226 B&O Road, Malott, Washington, in Okanogan County.
The regulated substance used at Chief Wenatchee-Malott is anhydrous ammonia
(CAS# 7664-41-7). The anhydrous ammonia is used as a refrigerant.
There are 14,000 pounds of anhydrous ammonia in the entire system.
Chief Wenatchee-Malott uses other hazardous substances on-site, however they are not listed in 40 CFR 68.130. However, Chief Wenatchee-Malott believes in the concept set forth in the "General Duty Clause" of the Clean Air Act. To this effect, Chief Wenatchee-Malott has established policies, procedures and training to reduce the risk of an accidental hazardous substance release for the safety of its employees and surrounding areas.
C. Worst-Case and Alternative Scenarios
The off-site consequence analysis considers two ammonia release scenarios identified as "worst case" and "alternative" scenarios. The
worst case scenario is defined by the Environmental Protection Agency (EPA), which states that "the owner or operator shall assume that the maximum quantity in the largest vessel is released ". The alternative scenario is defined as "more likely to occur than the worst case scenario".
Worst-Case Scenario - Failure of the largest vessel, filled to 100% capacity, would release 4,400 pounds of anhydrous ammonia. The release would occur inside the compressor room; its walls are in direct contact with the outside. Although the release scenario would occur inside a building, enclosure mitigation was not taken into account in the modeling of this release.
For the purpose of this worst-case scenario, it was assumed that all 14,000 pounds of ammonia were released in a 10-minute period. Under this assumption the distance to the toxic end-point of 0.14 mg/L is 2.2 miles. The "risk radius" extends past the boundaries of the plant, into public receptor areas. Distance was determined by us
e of RMP-COMP.
Alternative Release Scenario - Several alternative scenarios were modeled, using ALOHA, version 5.2.1, however a release from the bottom (liquid space) of the receiver, under normal operating conditions, was chosen. This alternative scenario provided the greatest risk radius, 1,100 yards. No mitigation factors were taken into account in the modeling of this scenario.
Both the worst-case and alternate scenarios are unlikely. A more realistic release scenario would be a vapor release from a pressure relief valve (PRV) lifting. These are located on top of the buildings, at a height of approximately 40 feet. In the event a PRV scenario which would involve the loss of the entire system inventory (14,000 pounds) over a 30-minute period, the end-point distance would be 850 yards. (As modeled by ALOHA)
D. General Accidental Release Prevention Program
Chief Wenatchee-Malott's accidental release prevention program is based on the following key elements:
7 Training of p
7 Preventative maintenance program
7 Use of safety equipment
7 Use of accurate and effective written operating procedures
Chief Wenatchee-Malott complies with:
7 OSHA's and Washington State's process safety management rule
7 Applicable Washington State's safety and environmental regulations
7 The IIAR (International Institute of Ammonia Refrigeration) standards for good work practices
The ammonia refrigeration system was installed to applicable standards and local codes at the time of installation. Piping and equipment is secured and protected; compressor (engine) room doors are tight fitting and open outwards. Other safety systems Chief Wenatchee-Malott utilizes include:
7 Computerized controls, which can be operated remotely
7 Suction trap hi-level float
7 High discharge pressure shut down
7 Low suction pressure shut down
7 High discharge temperature shut down
7 Oil pressure failure shut down
7 High amperes shut down
7 Automatic timer to prevent short cycling
7 Oil filt
ers plugged shut down
7 250 psi relief valves on high pressure side, to prevent overpressure situations
7 150 psi relief valves on low pressure side, to prevent overpressure situations
Operating Procedures and checklists have been prepared by Chief Wenatchee-Malott to be used by employees performing operational functions. Procedures are kept in the engine room and the refrigeration engineer's office. These procedures include:
7 Pre-start up procedures
7 Routine operations
7 Response to major and minor releases
7 Emergency action plan
E. Five-Year Accident History
Chief Wenatchee-Malott has not had any accidents involving ammonia in the last five years.
F. Emergency Response Program
In addition to the operating procedures, Chief Wenatchee-Malott has established Emergency Response Guidelines for r
eleases involving ammonia. These procedures instruct personnel to evacuate and notify 9-1-1 so that the public and public safety agencies will be notified.
G. Planned Safety Improvements
Chief Wenatchee-Malott plans on installing ammonia detectors in the compressor room and will continue to provide training to its employees.