Alcoa Inc., Warrick Operations - Executive Summary
Alcoa's Warrick facility has implemented a Risk Management Program to effectively manage risks to the public from accidental hazardous releases. This Risk Management Plan summarizes the elements of the RMProgram and is organized according to specific EPA RMP definitions and requirements, as follows:
7 Alcoa policies to protect health, environment, and safety;
7 Facility identification and regulated substances covered processes;
7 Hazard Assessment;
7 Prevention Program;
7 Five-Year Accident History;
7 Emergency Response Plan; and
7 Planned changes to improve safety.
The worst-case release scenario for a toxic involves a chlorine gas release due to a rupture of the largest vessel inventory of 90 tons from a railcar over a ten (10) minute period. This results in an impact distance of 25 miles using EPA's Offsite Consequence Analysis Guidance tables. This scenario is extremely unlikely. Alcoa Warrick Operations has never had an RMP incident involving chlorine that resu
lted in off-site impacts. One minor on-site incident has occurred in the last five years, involving a small release of chlorine from a process inside the building. No on-site or off-site RMP incidents have ever occurred involving the railcar within the last five years.
Alcoa Policies for Health, Environment, and Safety
It is Alcoa's policy to operate worldwide in a safe, responsible manner which respects the environment and the health of our employees, our customers and the communities where we operate. We will not compromise environmental, health or safety values for profit or production. All Alcoans are expected to understand, promote and assist in the implementation of this policy and the accompanying principles.
Facility Identification and Regulated Substances in Covered Processes
The Alcoa Warrick facility is located at Highway 66 in Newburgh, Indiana. The facility consists of a smelter and fabrication process, utilizing three chemicals that are regulated under 40 CFR 68
, EPA's Risk Management Program (RMP) Rule. These chemicals, chlorine, sulfur dioxide, and propane, are present at or above the minimum threshold levels for RMP applicability. The total maximum quantity in the process for these substances is listed below:
Chlorine: 180,000 pounds
Sulfur dioxide: 12,000 pounds
Propane: 220,500 pounds
Chlorine gas is used to remove impurities from the molten aluminum. Anhydrous sulfur dioxide is used to treat chromic acid in the wastewater, and propane is used as an on-site vehicle fuel.
Hazard Assessment - Worst Case Scenario
The worst case toxics accidental release scenario would be a failure of the chlorine railcar due to a rupture of the tank. Liquefied chlorine gas is transported to Alcoa via 90 ton railcar and loaded from the railcar directly into the ingot process. To minimize the potential of a chlorine release, there is a small intermediate storage of two to four days between car change outs. During a change out, residual chlorine i
n the system can be manually purged to a caustic neutralization system. Typically, one railcar of chlorine is used every six months. The maximum total chlorine in the process is 180,000 pounds. This quantity is assumed in the worst case scenario to be released over 10 minutes, as required by the RMP rule.
Hazard Assessment modeling shows that, under worst case weather conditions, the worst case release could produce a chlorine plume that could travel more than 25 miles before dispersing enough to no longer pose a hazard to the public. This Risk Management Plan includes information on mitigation and prevention measures implemented by Alcoa to reduce the risk of this type of event.
Worst case modeling for flammables (propane) does not impact any public receptor with a distance to endpoint of 0.40 miles.
Worst Case Release Mitigation Measures
Alcoa's preventative measures make it extremely unlikely that a significant chlorine release will occur. Active mitigation systems cannot b
e considered in modeling worst case scenarios for RMP; however, in the unlikely event that a release occurs, these systems should effectively reduce the risk associated with an RMP incident.
Hazard Assessment - Alternative Release Scenario
One alternative scenario for each regulated toxic was also modeled in the hazard assessment. A description of each follows. The Alternative Release Scenario for chlorine consists of simultaneous automated and manual failures of the system. These systems include
7 a complete rupture of the chlorine transfer hose from the railcar
7 failure of the automatic shutoff valves
7 failure of the detection system
7 failure of the ingot maintenance emergency response to fix the leak, and
7 failure of the HazMat Team to respond,
resulting in a release of chlorine. In this case, the plume was estimated to go 2.03 miles before dispersing enough to no longer pose a hazard to the public. The Alternative Release Scenario for SO2 was modeled for failure of th
e flexible hoses connecting the SO2 cylinders to the process, and the plume was estimated to go 1.15 miles before dispersing enough to no longer pose a hazard to the public. These scenarios are more likely than the Worst Case Scenario, but are still very unlikely events. There have been no actual releases which have caused off-site impacts for these toxics.
Alternative Release Mitigation Measures
While Alternative Release Scenarios are more likely to occur than the Worst Case Scenario, they are still very unlikely given Alcoa's prevention program. The mitigation systems should effectively reduce the risk associated with a release. Standard job procedures for chlorine unloading are followed by trained personnel. The railcar transfer hose is equipped with automatic shutoff valves. In the event of a leak, these valves can be closed either automatically, by the leak detection system or a power loss, or manually, by the emergency shutoff buttons. The manual shutoff valves can be
closed quickly following an early warning by the chlorine detectors, which sound a low level alarm at = ppm. A comprehensive fault-tree analysis of a severed liquid valve via the failure of the excess flow valve or the failure of the automatic shutoff valves determined a probability of occurrence of one in 38,000 years. A leak detection and monitoring system has also been installed in the SO2 feed system.
A prevention program is in place to minimize the risk of hazardous chemical releases in accordance with the Occupational Health and Safety Administration (OSHA) Process Safety Management (PSM) standard and the EPA Risk Management Program. This prevention program covers those processes that handle chlorine and SO2 above the threshold quantity of either PSM or RMP rules.
The prevention program provides a structured approach to preventing accidents. No prevention program is required for propane since there are no public receptors within a distance to an endp
oint from a worst-case release, no accidents have occurred, and emergency response is coordinated. Therefore, propane handling is program level 1.
Five-Year Accident History
During the past five years, there has been one incident involving a release of a regulated substance from covered processes that meet EPA criteria for the Five-Year Accident History, which are focused on serious accidents with either on-site deaths, injuries, or significant damage; or known off-site deaths, injuries, property damage, or environmental damage. The only incident involved one minor on-site injury resulting from a small quantity of chlorine released from the process. The employee's injury did not require a lost work day or any work restriction. No one off-site was injured, and there was no damage to off-site property. No injuries have occurred at the chlorine railcar.
Emergency Response Plan
It is Alcoa's policy in the event of a spill or release of materials to initiate activities to limit th
e spread of the released material and then immediately notify Plant Protection, who has been designated as the first-plant-contact. Plant Protection will respond to the scene in order to evaluate the nature of the situation and if the Fire Brigade or HazMat Team is required to respond. Actions are also coordinated with outside emergency response agencies, such as the Warrick County Fire Department, the Warrick E.M.S., and the Warrick County Sheriff's Department. Contact will then be made to an Emergency Response Coordinator in order to notify EPA. It should also be noted that Alcoa's on-site response team provides emergency medical, fire, and hazardous materials backup for local response teams, and Alcoa provides fire training for the local volunteer fire departments on-site. Alcoa is highly prepared to provide immediate response in the event of an accidental release and minimize the impact of such a release.
Planned Changes to Improve Safety
Safety remains an important aspect o
f the working environment at Alcoa. Chemical exposure risks have been minimized through ongoing internal risk reduction efforts as well as regulatory requirements. Chlorine usage on-site has been reduced more than 75% over the past eight years, and SO2 will be eliminated with the installation of the new wastewater treatment plant in 1999.