Chevron El Segundo Refinery - Executive Summary
1.0 EXECUTIVE SUMMARY |
Chevron's El Segundo Refinery began operations in 1911 making kerosene and other products. Since that time, the products and processes have expanded to include the making of gasoline, jet, diesel and other petroleum based products. Over the last 30 years, the government has undertaken more and more strenuous regulations of industrial air pollution and the prevention of major releases. As part of the Clean Air Act Amendments of 1990(CAA), the Environmental Protection Agency (EPA) was charged with overseeing the implementation of Section 112(r) of the Act.
This section of the CAA requires industrial facilities that handle certain toxic substances or flammables to prepare a Risk Management Plan (RMP) and implement an accidental release prevention program to prevent catastrophic releases of these substances into the environment and surrounding community. The Act also provides for public communication of this RMP to establish dialog between facilities and the s
urrounding community concerning the risks associated the plant.
This document presents El Segundo Refinery's RMP. The refinery handles quantities of anhydrous ammonia, aqueous ammonia and flammable substances in amounts over the EPA threshold limits for inclusion in an RMP. The RMP lists these chemicals, the quantities handled, and describes various scenarios whereby such substances could be released into the community. The facility's release prevention programs are also discussed. It should be noted that the refinery also handles other toxic substances that are not addressed in this document, even though the general refinery prevention programs do address them. The refinery is available to discuss its hazardous substances or the contents of this document with community members at (310) 615-5000 during business hours. During off-hours, emergency information requests or concerns should be directed to (310) 615-5342.
The Environmental Protection Agency has listed specific element
s to include in an RMP executive summary (40 CFR Part 68). The remainder of this summary follows a straight format that mirrors the agency's list.
1.1 Accidental Release Prevention and Emergency Response Policies
One of the key purposes of the prevention program is to establish a process safety system in facilities. Process safety is a before-the-fact accident prevention system with its foundations at the earliest stages of equipment design, maintenance and operation. The refinery routinely analyzes hazards and safeguards, and takes pro-active steps to ensure that incidents are prevented or that the consequences of an unlikely event are mitigated. Chevron El Segundo first established a Process Safety Management (PSM) program in the early 1990s as part of its OSHA compliance efforts. The EPA recognizes this program in the RMP regulations. This PSM program encompasses the following, and other, elements:
7 Training facility operators with regard to the safe handling of flammab
le and toxic substances;
7 Performing hazards analyses on new and existing plants at periodic intervals;
7 Ensuring that operating procedures, manuals and engineering information on the facility are kept up to date;
7 Ensuring the mechanical integrity of operating equipment through routine maintenance and inspection; and
7 Investigating all incidents that could have resulted in a major release or accident.
Should an emergency arise, the refinery has its own 24-hour fire department, staffed by trained full-time fire fighters. Fire fighters and emergency medical technicians are on site 24 hours per day, equipped to provide rapid first response to an incident. In addition, the refinery has an emergency response plan, and works closely with the El Segundo Fire Department on the response to fires or releases, public sheltering, and the coordination of other support service providers such as police or paramedics. The main city fire station is approximately half of a mile from the facilit
1.2 The Stationary Sources and Regulated Substances Handled
This RMP includes two toxic substances: anhydrous ammonia and aqueous ammonia.
Ammonia is generated in the normal course of refining petroleum in order to remove nitrogen from the crude oil. The removal of the nitrogen with hydrogen produces ammonia. The ammonia is first collected from the process in streams of water called "sour water." The ammonia is then removed as gaseous anhydrous ammonia from the sour water by distillation. A major percentage of the cleaned water can then be re-used in the refining process, thus reducing fresh water consumption.
The total quantity of anhydrous ammonia in the refinery is about 40,900 pounds. The single largest accumulation at any point within the refinery is an accumulator drum (V-833) which has the capacity of approximately 20,500 pounds of anhydrous ammonia. Normally, V-833 the level fluctuates between 25-40% full.
The anhydrous ammonia is combi
ned with fresh water at a blending facility inside the refinery to form a 30% solution (by volume) of aqueous ammonia. The total amount of aqueous ammonia in the refinery is approximately 2,210,000 pounds. Some of this aqueous ammonia is used inside the refinery to control nitrous oxide air pollution from process units. The majority of the aqueous ammonia, however, is sent to storage vessels at a loading rack. This ammonia is sold and shipped off-site as a co-product of the refinery. The largest single point accumulation of aqueous ammonia in the refinery is in vessel number V-691, which contains some 305,000 pounds of this 30% aqueous ammonia solution.
The refinery contains a large amount of flammable substances subject to the RMP. These range from the smallest compounds such as methane to larger ones such as pentane. Practically any process unit in the facility contains these substances in various mixtures. Since the process units and storage vessels vary in the
composition of flammables present, each was looked at separately. After review of the various units, the total quantity of regulated flammables in the refinery was estimated at 82,905,000 pounds. Because of their widespread distribution in the refinery, there are three different large vessels of interest because accidental release scenarios could impact different areas of the surrounding community. These vessels or tanks are:
7 T-715 (an LPG sphere with 6,273,000 pounds of liquefied propane and butane);
7 T-703 (a tank with approximately 3,591,000 pounds of liquefied butane and pentane); and
7 T-983 (a tank with contains about 3,508,000 pounds of liquefied butane and pentane).
1.3 RMP Offsite Consequence Analysis
This section describes the "worst-case release" and "alternative case release" scenarios for the toxic and flammable substances at the facility.
A "worst-case release" is defined by the EPA as a release of the entire largest single-point quantity in a scenario that wou
ld create the largest offsite consequence under worst-case atmospheric conditions and a rapid release rate. The offsite consequences are determined as the distances where the released substances can reach their "endpoints." For toxic substances the endpoints are defined as the concentrations that represent the maximums at which the agency believes that nearly all people could be exposed for up to one hour without serious or irreversible health affects. For flammable substances, the endpoint is defined as a one pound per square inch (1 psi) overpressure caused by an explosion of the released vapor cloud. One psi is sufficient to break windows. Since these worst-cases scenarios are based on extreme conditions, they are highly unlikely to occur. Two worst-case scenarios are presented to represent the regulated toxic substances handled at the refinery, and three are presented for all regulated flammable substances.
The "alternative-case" scenarios are presented as, although still u
nlikely, more realistic scenarios that could occur under abnormal conditions. One alternative release scenario is analyzed for each of the toxic substances registered in the RMP, and one alternative release scenario is presented for all flammable substances.
Based on a review of refinery information and processes, the worst-case scenarios for toxic substances were identified as a release of 20,500 pounds of anhydrous ammonia from vessel
V-833, and a release of about 93,800 pounds of 30% aqueous ammonia from a railcar. The potential consequences of these worst-case scenarios were modeled using the EPA's RMP*Comp program. During the analysis of off site consequences, no administrative controls were taken into account. The results indicated that there could be off-site consequences to the surrounding community under both worst case scenarios. The refinery is, however, self-contained with respect to runoff, so that no aqueous ammonia would escape the property.
ernative release scenarios were also reviewed for each of the registered toxic substances in the refinery. The selected alternative release scenario for anhydrous ammonia is based on similar past event that occurred to other pumps in similar service in the plant. In the RMP alternative scenario, the seal in pump P-834 failed, and released about 160 pounds of anhydrous ammonia before it could be mitigated. The analysis indicated no consequences to the population or environment outside the refinery.
The alternative release scenario for aqueous ammonia involved a release from a railcar into an area with an underground capture tank. This scenario was based on a similar past event that resulted in a small quantity release of aqueous ammonia. In the scenario evaluated for RMP purposes, about 60,000 pounds of aqueous ammonia was released. Of that, about 70% of the spill drained into the underground containment; the remaining 30% was assumed to be splashed on the area surrounding the ra
ilcar. Ammonia vapor then evaporated from the splashed area and traveled downwind of the release source. The control measures, in this case, included the underground storage collection tank that limited the size of the accumulated pool on the surface. Other control measures included the onsite fire department equipped to mitigate the spill. The results of this analysis indicated no potential offsite consequences.
In the case of flammable substances, there are worst-case release scenarios from three different vessels that could affect different areas outside the refinery. As a result, these three worst-case release scenarios are presented in the RMP. These are as follows:
7 A vapor cloud release and explosion from T-715;
7 A vapor cloud release and explosion from T-703;
7 A vapor cloud release and explosion from T-983.
The potential scenarios were analyzed for all three of the above using the EPA's RMP*Comp program. The end-point effect was determined to
be a 1 psi blast overpressure. No administrative controls or mitigation measures were considered in the calculation of end point distances. The results of the analysis indicated that there were offsite impacts from all three of these scenarios.
One alternative release scenario was analyzed for all registered regulated flammables in the refinery. This scenario involves the release of 47,500 pounds of propane due to a hypothetical hose rupture. The scenario was analyzed using the vapor cloud explosion model with 1 psi overpressure as the endpoint. Onsite mitigation measures include the onsite fire department that is equipped to contain and control spills and fires. The analysis indicated no offsite consequences.
It should be noted that we have 16 other regulated process units that handle flammable substances (Program 1) whose worst case scenarios do not reach the community or other public receptors. The worst case scenario in each case is a vapor cloud explosion from the largest
vessel in the process unit, with no passive mitigation taken into account.
1.4 General Accidental Release Prevention Program and Prevention Steps
As discussed above, the refinery has been working with a PSM program under OSHA since the early 1990's. The EPA recognized this OSHA process in the development of the RMP program. The OSHA program satisfies the RMP requirements for a prevention program. The refinery's PSM program elements include:
7 Process Safety Information
7 Process Hazards Analysis
7 Operating Procedures
7 Mechanical Integrity
7 Management of Change
7 Pre-startup Safety Review
7 Compliance Audits
7 Incident Investigation
7 Employee Participation
7 Hot Work Permits
The facility has fully implemented these elements under the OSHA standard. Additional prevention steps specific to ammonia include refinery specifications for new piping and equipment in ammonia service. These specifications exceed most typical requirements for oil-handling e
quipment due to the unique hazards of ammonia. The specifications include features such as having high reliability valves, minimal connections, using heat treated metals in vessels, selection of metals resistant to embrittlement during auto-refrigeration, and more isolation valves on liquid lines.
1.5 Five Year Accident History
There were two incidents meeting the criteria for inclusion in this RMP in the last five years. Two involved a toxic substance, and one involved flammable substances.
The most recent of these incidents was a release of aqueous ammonia that resulted in an injury to an employee on 7/25/98. Ammonia from a railcar sprayed the operator and about 510 pounds of the ammonia spilled to the ground. A nearby operator rescued the employee and summoned the Chevron fire department. The employee was hospitalized and the ammonia was cleaned up. There were no offsite consequences.
On 8/2/96, an incident involved a release of fuel gas from a burner that ignited and
burned an employee. The fuel gas release was brought under control, and there were no offsite consequences.
1.6 Emergency Response Program
The refinery maintains a full-time fire department with equipment that meets the needs of responding to refinery fires and releases of chemicals. An emergency response plan has been developed to address the following:
7 Specific actions to take in a response to an accidental release of hazardous chemicals;
7 Procedures for informing the public and the local agencies;
7 Information on emergency health care;
7 Information on how to communicate with the local emergency response agency;
7 Identification, maintenance, inspection and testing of emergency equipment; and
7 Training information.
This plan was developed in consultation with the local fire department. The refinery fire fighters and emergency response personnel routinely drill and train to maintain their skills in emergency response.
1.7 Planned Changes to Improve Safety
Here are a
few of the refinery's initiatives to improve employee and public safety:
The refinery has undertaken a process to positively identify the metallurgy of metals used in the field by non-destructive testing. This on-going effort involves inspectors reviewing both new and existing materials to ensure that they meet specifications for the designated service. The refinery plans to continue this program to improve safety and reliability.
The refinery is building three weather stations to remotely report meteorological information. Once completed, emergency responders will be able to access the centralized computer system to determine wind direction to monitor releases.
Over the past few years, the refinery has implemented a behavioral-based safety process that focuses on employee safety behavior. Employees observe other employee's at work and then discuss safe and at risk behaviors that were witnessed. The findings in each observation are entered in a refinery database. The database
information is shared at each workgroup's monthly safety meeting and used in problem solving. This program is in addition to the PSM program described earlier in this document.
Communication between shifts and days off has been improved by this year's deployment of electronic turnovers. Employees have easy access to new and archived information to allow operators to run their plants more efficiently and safer. This will be the first year that all divisions will be "on-line."