Clear Lake Plant - Executive Summary
ACCIDENTAL RELEASE PREVENTION AND EMERGENCY RESPONSE POLICIES |
At Celanese's Clear Lake Plant we are committed to operating and maintaining all of our processes in a safe and responsible manner. We use a combination of accidental release prevention programs and emergency response planning programs to help ensure the safety of our employees and the public as well as protection of the environment. This document provides a brief overview of the comprehensive risk management activities that we have designed and implemented, including:
* A description of our facility and use of substances regulated by EPA's RMP regulation
* A summary of results from our assessment of the potential offsite consequences from accidental chemical releases
* An overview of our accidental release prevention programs
* A five-year accident history for accidental releases of chemicals regulated by EPA's RMP rule
* An overview of our emergency response program
* An overview of planned improvem
ents at the facility to help prevent accidental chemical releases from occurring and adversely affecting our employees, the public, and the environment
STATIONARY SOURCE AND REGULATED SUBSTANCES
Our facility produces mainly commodity organic chemicals using a variety of chemicals and processing operations. The major products manufacured at the facility are acetic acid, vinyl acetate, acrylic acid, acrylate esters, methanol, ethylene oxide, ethylene glycol, and ethoxylates. In our processes, we use the following chemicals that EPA has identified as having the potential to cause significant offsite consequences in the event of a substantial accidental release:
-Ethylene oxide, produced at a rate of 600 million lbs/yr, is used mainly for the local production of ethylene glycol, with the remainder used for the production of ethoxylates or sold in the merchant market. The material is stored on site in pressurized and refrigerated spheres.
-Sulfur dioxide is used as a raw mater
ial in the ethoxylates unit. The material is stored in the unit as pressurized liquefied gas in a 6,000 gal. storage tank. Although ethylene oxide is used also as a raw material, there's no storage of this chemical in the unit.
-Vinyl Acetate, produced at a rate of 580 million lbs/yr, is sold entirely in the merchant market. The material is stored on site in inerted atmospheric tanks.
-Acetaldehyde is a byproduct in the production of vinyl acetate. It is recovered and shipped to another company location to be used as a raw material. About 800,000 lbs are stored on site as a liquid in a pressurized sphere.
Our accidental release prevention programs and our contingency planning efforts help us effectively manage the hazards that are posed to our employees, the public, and the environment by our use of these chemicals.
KEY OFFSITE CONSEQUENCE ANALYSIS SCENARIOS
EPA's RMP rule requires that we provide information about the worst-case release scenarios and alternative r
elease scenarios for our facility. The following are brief summaries of these scenarios, including information about the key administrative controls and mitigation measures to limit the exposure distances for each scenario:
Worst-Case Scenario - Regulated Toxic Chemicals
An ethylene oxide (EO) Worst Case Scenario (WCS) was selected to represent the toxic chemicals WCSs at our facility since it reaches the farthest and all the environmental receptors of all other cases are included in this case. In this case, a sudden rupture of our largest EO sphere, which contains 1.5 million lbs of refrigerated liquid EO, would produce a release with offsite consequences, reaching local area public receptors. As dictated by the regulation, the only mitigation considered was a system of dikes and flumes that would contain the entire amount in a retention pond. Equations from EPA's RMP Guidance for Chemical Distributors (Jan. 99) were used for these calculations.
Alternative Release Scenarios -
Regulated Toxic Chemicals
The ARS for ethylene oxide (EO) is based on the rupture of a 2" line coming from the largest storage vessel (described in the WCS). Active and passive systems would minimize this release: EO detectors would alert operators who would isolate the system with remotely actuated valves in less than 10 minutes. The released material, about 22,000 lbs in those 10 minutes, would have offsite consequences. Only industrial areas would be affected.
The ARS for sulfur dioxide involves a 2" line rupture during loading operations from the delivery truck. The operator in attendance, who is required to be fully suited with a fresh air mask would shut off the valve well within 3 minutes, allowing a maximum release of 5,400 lbs. This release would extend just a little outside plant boundaries. Only industrial areas would be affected.
The ARS for VA involves also a 2" line rupture from a storage vessel. The release would be detected and stopped with the help of alarms
and using remote shutoff valves within 10 minutes. The released material, about 32,800 lbs, would have a toxic end point a little outside plant boundaries. Only industrial areas would be affected.
Worst-case Release Scenario - Regulated Flammable Chemicals
Acetaldehyde is the only covered flammable at our facility. A Worst Case Scenario (WCS) involving this chemical would be a sudden rupture of our acetaldehyde sphere, which contains 820,000 lbs of the material. The WCS would be a Vapor Cloud Explosion with offsite consequences, having an endpoint (1 psi overpressure) a little outside plant boundaries. Only industrial areas would be affected. The material was treated as a gas for this scenario and no mitigation was considered. EPA's OCA Tables were used for these calculations.
Alternative Release Scenario - Regulated Flammable Chemicals
The alternative release scenario would involve the rupture of a 2" line from the storage vessel described above. The leak would be detect
ed and isolated within 10 minutes. The endpoint (1 psi overpressure) would be well within the plant boundaries.
We are using this information to help us ensure that our emergency response plan and the community emergency response plan address all reasonable contingency cases.
GENERAL ACCIDENTAL RELEASE PREVENTION PROGRAM AND CHEMICAL-SPECIFIC PREVENTION STEPS
We take a systematic, proactive approach to preventing accidental releases of hazardous chemicals. Our management systems address each of the key features of successful prevention programs including:
* Process safety information
* Process hazard analysis
* Operating procedures
* Mechanical integrity
* Management of change
* Pre-startup review
* Compliance audits
* Incident investigation
* Employee participation
* Hot work permit
As part of our prevention efforts, we have implemented the following chemical-specific prevention steps:
In the ethylene oxide process:
* use of s
ealless pumps to avoid leaks
* use of rigid insulation with stainless steel sheaths and banding for better fire protection
* use of both refrigeration and pressure in the storage of ethylene oxide to assure keeping it liquid in case of a release
* use of a large capacity deluge system around the ethylene oxide storage spheres to avoid forming a vapor cloud
* limit the level to which a tank can be filled
In the vinyl acetate process:
* use of nitrogen blanketing in all storage tanks to avoid flammability
* use of mounted water spray around the acetaldehyde sphere to prevent formation of a vapor cloud in case of a release
In the ethoxylates process for the unloading of SO2 to the storage vessel:
* use of excess flow valves
* presence of fully protected (acid suits, fresh air masks) operators
* video cameras
* vessel remote isolation capabilities
* gas monitors
These individual elements of our prevention program work together to prevent accidental chemical release
s. Our company and our employees are committed to the standard that these management systems set for the way we do business, and we have specific accountabilities and controls to ensure that we are meeting our own high standards for accident prevention. We are in compliance with the OSHA process safety management rule and this RMP rule.
FIVE-YEAR ACCIDENT HISTORY
We keep records for all significant accidental chemical releases that occur at our facility. During the past five years there has not been a release involving materials covered under EPA's RMP rule that either had any offsite impact or a significant plant impact. In one incident in the ethylene oxide unit an operator was injured. In this 1996 incident an operator got his feet exposed to a dilute solution of ethylene oxide during an equipment clearing operation, resulting in burns that required medical attention.
For each incident, whether it involves a covered chemical or not, we have conducted formal incident investig
ations to identify and correct the root causes of the events.
EMERGENCY RESPONSE PROGRAM
We maintain an integrated contingency plan, which consolidates all of the various federal, state, and local regulatory requirements for emergency response planning. Our program provides the essential planning and training for effectively protecting workers, the public, and the environment during emergency situations. We are a member of CIMA (Channel Industries Mutual Aid), a consortium of area companies that coordinates and help each other during emergencies in which the individual plant's resources may not be sufficient to effectively handle the response.
PLANNED CHANGES TO IMPROVE SAFETY
As a result of the PHAs (Process Hazards Analyses) that are conducted periodically on each of the units of the plant, recommendations to improve the prevention of, and response to accidental chemical releases are generated. The plant is committed to implementing all the PHA recommendations that are approve
d. Examples of recently implemented recommendations in the ethylene oxide unit include (i) addition of a mechanical stop in an compressor system to avoid deadheading, and (ii) increased testing of the automatic shutdown system to increase its reliability; in the vinyl acetate unit (i) removed a line to avoid inadvertent mixing, and (ii) added an independent high alarm to a tank to avoid overfilling; in the ethoxylates unit (i) changed procedures to have at least two people in the SO2 off-loading operation and wearing fresh air masks, and (ii) installation of remote valves for isolation in case of a line break.
In addition, besides PHA recommendations, inventories have been reduced in the ethylene oxide unit, and a flare system added to avoid having environmental releases in case of a potential emergency release.
The following is a list of improvements that are being implemented at the facility to help prevent and/or better respond to accidental chemical releases:
- Reformatting all
the facility's Standard Operating Procedures (SOPs) to make them clear and concise and ensure inclusion of human factors.
- Setting tighter restrictions on approval and general notifications before removing or replacing safety equipment in service (e.g., fire suppression, overspeed trip devices, etc.)
- Providing guidelines for conduct of shift relief to maximize the quality and quantity of information shared at shift change.
- Setting a policy that mandates independent verification of equipment by operations prior to placing into service after maintenance.
- Requiring a very structured process for the release of equipment by operations to maintenance and vice versa.
- Setting minimum standards for equipment labeling.