Genpak LLC - Cedar City - Executive Summary
A. Description of Stationary Source and Regulated Substances Handled |
Genpak LLC (Genpak) produces foamed polystyrene food trays and containers using a single screw and tandem system of extruding expanded polystyrene foam sheets. The process takes polystyrene pellets through an extrusion process where a nuclient and blowing agent (isopentane) are added. The sheets are then thermoformed and cut to produce the final product.
Isopentane is delivered to the Genpak - Cedar City, Utah facility via railcar. The railcar is unloaded into an aboveground storage tank using a transfer pump. A vapor recovery system prevents the release of isopentane vapors to the atmosphere during the transfer. Isopentane is pumped from the storage tank to the isopentane pump room where the pressure is increased so it can be injected into one of the three extruders.
As a result of the manufacturing process, isopentane is stored at the facility in quantities that exceed the threshold quantity specified b
y EPA regulations. Genpak - Cedar City has one covered process that requires compliance with Program 1 of the EPA Risk Management Program (RMP) regulation.
B. Accidental Release Prevention & Emergency Response Policies of Genpak
Genpak - Cedar City is committed to protecting facility personnel, the public and the environment from any workplace and accidental release hazards. Appropriate responses to releases of regulated chemicals are documented in the Hazard Communication Plan.
Safety, environmental protection and risk management programs are fully implemented and coordinated with community emergency responders for emergency planning and response efforts.
C. Release Scenario Discussion
The following is a brief description of the worst-case release scenario that is being submitted by Genpak in the Risk Management Plan (RMPlan). The Federal Register dated May 26, 1999 (Volume 64, Number 101) page 28697 states that the following changes to ' 68.25 have been made by EPA: "
For regulated flammable substances that are normally liquids at ambient temperatures, the owner or operator shall assume that the entire quantity in the vessel or pipe, as determined under ' 68.25(b), is spilled instantaneously to form a liquid pool. The owner or operator shall assume that the quantity which becomes vapor in the first 10 minutes is reported as the quantity released." Genpak elected to use the look-up tables contained in the EPA Offsite Consequence Analysis Guidance document (April 1999) to calculate estimated release rates and to determine the distances to the appropriate flammable endpoints.
Therefore, the worst-case release scenario for Cedar City, UT involves the rupture of the 30,000 gallon (155,100 pounds) isopentane storage tank. The entire contents of the isopentane storage thank is spilled instantaneously to form a liquid pool in the diked area located underneath the storage tank. The quantity of isopentane that is evaporated from the liquid pool in the fi
rst ten minutes of the release was then assumed to form a vapor cloud within the upper and lower flammability limits, and the cloud detonates. Ten percent of the flammable vapor in the cloud is assumed to participate in the explosion. Using Equation C-1 from the guidance document, the distance to an overpressure level of 1 psi from the explosion of the vapor cloud was calculated to be 0.11 miles (581 feet). There are no public or environmental receptors within the 0.11 mile radius.
D. Five-year Accident History
Under the EPA RMP regulations, an accidental release is defined as a release of a regulated substance that "resulted in deaths, injuries or significant property damage on-site, or known off-site deaths, injuries, evacuations, sheltering in place, property damage, or environmental damage." Within the past five years, the Genpak - Cedar City, UT facility has had no accidents that meet these requirements.
E. General Accidental Release Prevention Program
ak - Cedar City facility complies with the RMP regulation requirements for its Program 1 covered process.
F. Emergency Response Program
Genpak will only respond to incidental releases of isopentane where the release can be absorbed, neutralized, or otherwise controlled at the time of release by employees in the immediate release area, or by maintenance personnel. For non-incidental releases Genpak will rely on outside responders. Therefore, Genpak has coordinated response actions with the local fire department and ensured that appropriate mechanisms are in place to notify emergency responders when there is a need for response.
G. Planned Changes to Improve Safety
Genpak - Cedar City believes that the existing safety program is adequate. However, if any changes occur in the future which affect the isopentane process, these changes will be thoroughly reviewed to ensure that the safety of Genpak employees and neighbors is not compromised.