United States Cold Storage, Laredo II - Executive Summary
United States Cold Storage, Inc. is committed to the safe operation of all our facilities to protect our workers, the public and the environment. This is accomplished to a great extent by a well developed, up-to-date and implemented Risk Management Program. All USCS facilities shall operate in a prudent and safe manner. It shall be the responsibility of the plant manager to ensure that all procedures are followed as set forth in our Risk Management and Process Safety Management programs. In the unlikely event of an accidental release it is USCS policy to immediately call the National Response Center, Local Emergency Response Committee, the local Fire Department and other agency(ies) that may be required. All USCS facilities will have an emergency response team to assist these agency(ies). |
United States Cold Storage, Laredo is a public refrigerated warehouse that uses anhydrous ammonia as a refrigerant in a closed loop system. Anhydrous ammonia, most commonly known as ammonia, is an ex
cellent refrigerant and is commonly used in most of the world's industrial refrigeration systems. Ammonia has an excellent warning property, its odor. Ammonia's odor is familiar to most people due to the fact that it is commonly used in household cleaning solutions. Ammonia can be detected as low as 5 parts per million (PPM) and has an average life span of 7 days in the environment before it breaks down to its common elements nitrogen and hydrogen.
Typical items stored within USCS facilities are raw or processed food items that can be found in your supermarket or local restaurant. Temperatures range between -10 degrees to +45 degrees F. The refrigeration equipment and piping are located throughout the facility. The condensers and related piping are on the machine room roof with the piping to and from the freezers, coolers, truck and rail docks located on dock roofs. The machine room contains most of the large refrigeration machinery and vessels. In an unlikely event of a refriger
ant leak in a refrigerated space, the ammonia vapor would be contained inside the space, due to the vapor tight construction of the facility. It then may be treated and/or vented under controlled conditions. The facility is equipped with ammonia detectors throughout to help lessen any leaks that might occur and to provide an early alert.
USCS believes that prevention is foremost. All of USCS facilities are maintained by a staff of trained maintenance personnel. Most of these people are members of the Refrigerating Engineers and Technicians Association (RETA) and all Chief Engineers are members of the International Institute of Ammonia Refrigeration (IIAR) and hold a RETA Certification Level A. USCS has on staff at the corporate level an OSHA and EPA coordinator/trainer who is a certified OSHA Instructor. All facilities comply with OSHA's Process Safety Management without regard to the ammonia threshold quantity. All the vessels and piping have been installed according to ASME vess
el and piping codes and applicable local Building, Fire and Mechanical Codes. The Laredo facility was engineered and built to a Seismic 4 Earthquake Code.
The facility's emergency response program is based on the OSHA requirements for 29 CFR 1910.38-Emergency Action Plan, OSHA's 1910.119, Process Safety Management and 1910.120 HAZWOPER standards. We have trained employess for emergency response and maintain a written emergency response plan.
FIVE-YEAR ACCIDENT HISTORY:
The USCS Laredo facility has been operating at this location for the past 10 years. Within that history the facility has seen no refrigerant releases. Since June, 1994, this facility has not experienced any accidents or releases from their refrigeration system(s) that resulted in deaths, injuries or significant property damage on site or offsite, deaths, injuries, evacuations, sheltering in place, property damage or environmental damage.
OFFSITE CONSEQUENCE ANALYSIS:
Worst-case release scenario analysis: As require
d by law under 40 CFR Part 68.25, Worst-case release scenario analysis, an analysis was prepared for the Laredo facility. The United States Environmental Protection Agency's Risk Management Program Guidance for Ammonia Refrigeration look-up tables and formulas were used for this analysis. This worst-case release scenario is estimated to create the greatest distance in any direction to an endpoint of 200 ppm from the accidental release of anhydrous ammonia used as a refrigerant in a closed-loop refrigeration system. The quantity release was based on a "Worst-case" release scenario for a toxic gas liquified under pressure that is normally a gas at ambient temperature. The release was generated from the facility's Low Temperature Pump Receiver. Releasing 250 pounds per minute for a 10 minute period with passive mitigation system in place, inside a facility. The Laredo facility has offsite consequence.
The dispersion analysis used a wind speed of 1.5 meters per second and an "F" atmosphe
ric stability class. With an ambient temperature of 77 degrees F (25C) and a relative humidity of 50%. Using a release height at ground level and a surface roughness class of Urban. Dense gas was used for gas density.
Alternative Release Scenario Analysis: As required by law under 40 CFR Part 68.28, Alternative release scenario analysis was prepared for the Laredo facility. The United States Environmental Protection Agency's Risk Management Program Comp a computer based program was used for this analysis. This alternative release scenario is estimated to create a distance to reach off-site in any direction to an endpoint of 200 ppm from an accidental release of ammonia used as a refrigerant in a closed-loop refrigeration system. The Laredo facility has offsite consequence.
The alternative release scenario was a mechanical seal failure on an ammonia pump for the low temperature pump receiver. The mechanical seal failure was identified through the review of our process hazard analysis
(PHA) for the Laredo facility's What-If Study. The failure scenario was identified under Subsystem(s) High and Low Temperature Pump receiver, What-If question #3. Passive mitigation system was in place, release inside the facility. The following administrative controls are in place: Engine room log is maintained, with visual checks of all of the equipment including the amonia pumps. Oil that is added to the refrigeration equipment is noted on the Daily Engine Room Log. Annual preventive maintenance of the refrigeration equipment includes the ammonia pumps. Housekeeping of the engine room area includes wiping up and investigating oil leaks and moping the floors on a daily to weekly bases.
The first PHA re-vaildation recently performed for this facility produced no recommendations to improve safety. However the first PHA produced 5 recommendations to improve safety at the Laredo facility. Such recommendations included installation of new mitigation and/or controls, equipment.