The Dow Chemical Company-Grand Bayou Operations - Executive Summary
Risk Management Program Executive Summary
The Dow Chemical Company
Grand Bayou Operations
1. Accidental Release Prevention and Emergency Response Policies
We at The Dow Chemical Company-Grand Bayou Operations are strongly committed to employee, public and environmental safety. This commitment is demonstrated by our comprehensive accidental release prevention program that covers areas such as design, installation, operating procedures, maintenance, and employee training associated with the processes at our facility. It is our policy to implement appropriate controls to prevent possible releases of regulated substances. However, if a release should occur, we are coordinated with the Assumption Parish Office of Emergency Preparedness, which provides additional emergency response expertise.
2. The Stationary Source and the Regulated Substances Handled
The Grand Bayou Operations primary activity includes the solution mining of salt from the Napoleonville Dome, which is located in As
sumption Parish, encompassing a surface area of approximately 1670 acres. Dow's operations on the Napoleonville Salt Dome began in 1957 with the drilling and mining of the Grace No. 1 well. Since then, an additional 29 Dow operated caverns have been mined into the dome. Fifteen of the active carverns are in hydrocarbon service with total storage capacity in excess of 38 million barrels. Nine caverns are in mining service with a saturated brine deliverability of 8500 gallons per minute. We have 8 regulated substances present at our facility. These substances include Ethane, Butane, Pentane, Propylene [1-Propene], Methane, Ethylene [Ethene], Propane and Chlorine.
The maximum inventory of Ethane at our facility is 180,000,000 lbs. while Butane, Pentane, Propylene [1-Propene], Methane, Ethylene [Ethene], Propane and Chlorine are present at our facility in quantities of 37,000,000 lbs., 160,000,000 lbs., 64,000,000 lbs., 850,000 lbs., 120,000,000 lbs., 250,000,000 lbs., and 8000 l
3. The Worst Case Release Scenarios and the Alternative Release Scenarios, including administrative controls and mitigation measures
To evaluate the worst case scenarios, we have used the EPA's OCA Guidance Reference Tables or Equations. For alternative release scenario analyses we have employed the EPA's OCA Guidance Reference Tables or Equations and the modeling program PHAST. The following paragraphs provide details of the chosen scenarios.
The worst case release scenario submitted for Program 3 toxic substances as a class involves a catastrophic release. In this scenario 2000 lb. of Chlorine is released in a gaseous form over 10 minutes. At Class F atmospheric stability and 1.5 m/s windspeed, the maximum distance of 5.6 miles is obtained corresponding to a toxic endpoint of 0.0087 mg/L.
The alternative release scenario for Chlorine involves the release of 2000 lbs. of chlorine in a gaseous form over 10 minutes. Under neutral weather conditions, the maxim
um distance to the toxic endpoint of 0.0087 mg/L of Chlorine is 2.0 miles.
The worst case release scenario submitted for Program 3 flammable substances as a class involves a catastrophic release. In this scenario 1,500,000 lbs. of Pentane is released. It is assumed that the entire quantity is released as a vapor, which finds an ignition source, with 10 percent of the released quantity participating in a vapor cloud explosion. Under worst case weather conditions, the calculated distance of 0.9 miles is obtained corresponding to an endpoint of 1 psi overpressure.
An additional worst case release scenario for Program 3 flammables, involving a catastrophic release, is also included in the RMP because it affects different offsite receptors. In this scenario 1,500,000 lbs. of Propylene [1-Propene] is released. It is assumed that the entire quantity is released as a vapor, which finds an ignition source, with 10 percent of the released quantity participating in a vapor cloud explosion
. Under worst case weather conditions, the calculated distance of 0.9 miles is obtained corresponding to an endpoint of 1 psi overpressure.
The alternative release scenario submitted for Program 3 flammable substances involves a release of Propane. The release is assumed to result in a Jet fire. The scenario involves the release of 12,770 lbs. of Propane in 10 minutes. Under neutral weather conditions, the maximum distance to the flammable endpoint is 0.04 miles.
4. The General Accidental Release Prevention Program and the Chemical-Specific Prevention Steps
Our facility has taken all the necessary steps to comply with the accidental release prevention requirements set out under 40 CFR part 68 of the EPA. The following sections briefly describe the elements of the release prevention program that is in place at our stationary source.
Process Safety Information
The Dow Chemical Company-Grand Bayou Operations maintains a detailed record of safety information that describes the c
hemical hazards, operating parameters and equipment designs associated with all processes. Some of this documentation includes Material Safety Data Sheets, equipment spec sheets, and reactive chemicals tests.
Process Hazard Analysis
Our facility conducts comprehensive studies to ensure that hazards associated with our processes are identified and controlled efficiently. The methodology used to carry out these analyses is What If/Checklist (combined), HAZOP, the Dow Fire and Explosion Index, the Dow Chemical Exposure Index, and Reactive Chemicals/Process Hazards Analysis. The studies are undertaken by a team of qualified personnel with expertise in engineering and process operations and are revalidated at a regular interval of 3 years. Findings related to the hazard analysis are addressed in a timely manner. The most recent PHA/update was performed on 03/23/1999.
For the purposes of safely conducting activities within our covered processes, The Dow Chemical
Company-Grand Bayou Operations maintains written operating procedures. These procedures address various modes of operation such as initial startup, normal operations, temporary operations, emergency shutdown, emergency operations, normal shutdown and startup after a turnaround. The information is regularly reviewed and is readily accessible to operators involved in the processes.
The Dow Chemical Company-Grand Bayou Operations has a comprehensive training program in place to ensure that employees who are operating processes are competent in the operating procedures associated with these processes.
The Dow Chemical Company-Grand Bayou Operations carries out highly documented maintenance checks on process equipment to ensure proper operations. Process equipment examined by these checks includes among others; pressure vessels, storage tanks, piping systems, relief and vent systems, emergency shutdown systems, controls and pumps. Maintenance operati
ons are carried out by qualified personnel with previous training in maintenance practices. Furthermore, these personnel are offered specialized training as needed. Equipment deficiencies identified by the maintenance checks are corrected in a safe and timely manner.
Management of Change
Written procedures are in place at The Dow Chemical Company-Grand Bayou Operations to manage changes in process chemicals, technology, equipment and procedures. The most recent review/revision of maintenance procedures was performed on 01/04/1999. Process operators, maintenance personnel or any other employee whose job tasks are affected by a modification in process conditions are promptly made aware of and offered training to deal with the modification.
Pre-start up safety reviews related to new processes and to modifications in established processes are conducted as a regular practice at The Dow Chemical Company-Grand Bayou Operations. The most recent review was performed
on 04/01/1999. These reviews are conducted to confirm that construction, equipment, operating and maintenance procedures are suitable for safe startup prior to placing equipment into operation.
The Dow Chemical Company-Grand Bayou Operations conducts audits on a regular basis to determine whether the provisions set out under the RMP rule are being implemented. The most recent compliance audit was conducted on 11/20/1997. These audits are carried out at least every 3 years and corrective actions required as a result of the audits are undertaken in a safe and prompt manner.
The Dow Chemical Company-Grand Bayou Operations promptly investigates any incident that has resulted in, or could reasonably result in, a catastrophic release of a regulated substance. These investigations are undertaken to identify the situation leading to the incident as well as any corrective actions to prevent the release from reoccurring. All reports are retained
for a minimum of 5 years.
The Dow Chemical Company-Grand Bayou Operations truly believes that process safety management and accident prevention is a team effort. Company employees are strongly encouraged to express their views concerning accident prevention issues and to recommend improvements. In addition, our employees have access to all information created as part of the facility's implementation of the RMP rule, including information resulting from process hazard analyses in particular.
Our company hires contractors to conduct specialized maintenance, construction and various other activities. Prior to selecting a contractor, a thorough evaluation of safety performance of the contractor is carried out. The Dow Chemical Company-Grand Bayou Operations has a system in place to inform the contractors of known potential hazards related to the contractor's work and the processes. Contractors are also required to inform Dow Chemical Company of a
ny hazards they may introduce at the site.
5. Five-year Accident History
The Dow Chemical Company-Grand Bayou Operations has had an excellent record of preventing accidental releases over the last 5 years. Due to our release prevention policies, there has been no accidental release as defined by the RMP rule of regulated substances during this period.
6. Emergency Response Plan
The Dow Chemical Company-Grand Bayou Operations has a written emergency response plan to deal with accidental releases of hazardous materials. The plan includes all aspects of emergency response including adequate first aid and medical treatment, evacuations, notification of local emergency response agencies and the public, as well as post-incident decontamination of affected areas.
To ensure proper functioning, our emergency response equipment is regularly inspected and serviced. In addition, the plan is promptly updated to reflect any pertinent changes taking place within our processes that would requ
ire a modified emergency response.
Assumption Parish OEP is the Local Emergency Planning Committee (LEPC) with which our emergency plan has been coordinated and verified.
7. Planned Changes to Improve Safety
There are no planned changes at this time as a result of our implementing the accidental release prevention program.