La Porte Site - Executive Summary
General Executive Summary |
The Dow Chemical Company
La Porte Site
1. Accidental Release Prevention and Emergency Response Policies
We at La Porte Site 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 all chemicals including regulated substances. Unforeseeably, if such a release does occur, our highly trained emergency response personnel are on hand to control and mitigate the effects of the release. We are also coordinated with Channel Industries Mutual Aid (CIMA) which provides additional emergency response expertise.
2. The Stationary Source and the Regulated Substances Handled
Our primary activities encompass The Dow Chemical Compa
ny facility in La Porte, Texas, which is in the chemical manufacturing business. The basic products manufactured at the site include Methylene Diphenyldiisocyanate based (MDI based) polymeric isocyanates, polyol systems, related polyurethane elastomers and foams, and phosgene. Chloroformate chemicals are produced at this facility also. We have six regulated substances present at our facility, which are involved in several uses. These substances include Chlorine, Formaldehyde (solution), Ammonia (anhydrous), Methyl Chloroformate, Propyl Chloroformate, and Phosgene [Carbonic dichloride]. Chlorine is used for phosgene production. Formaldehyde (solution) is used for polymeric amine production. Ammonia (anhydrous) is used for phosgene leak mitigation. Phosgene [Carbonic dichloride] is used for polymeric isocyanate production. Methyl and propyl chlorofomates are sold as specialty chemical intermediates.
The maximum inventory of Chlorine at our facility is 181797.68 lb. while Form
aldehyde (solution), Ammonia (anhydrous) and Phosgene [Carbonic dichloride] are present at our facility in quantities of 92400.00 lb., 26500.00 lb. and 17346.00 lb. respectively. The maximum inventory of methyl and propyl chlorofomates are 200,000 lbs. each.
3. The Worst Case Release Scenario(s) and the Alternative Release Scenario(s), including administrative controls and mitigation measures to limit the distances for each reported scenario
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 Phast version 5.1. 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 from Polymeric MDI Production. In this scenario 17346 lb. of liquid Phosgene [Carbonic dichloride] is released. The toxic liquid released is assumed to form a 1-cm deep pool from w
hich evaporation takes place. The entire pool is estimated to evaporate over 10 minutes. The released quantity has been limited to 20 % of the maximum capacity of the source by a system of administrative controls. At Class F atmospheric stability and 1.5 m/s windspeed, the maximum distance of >25 miles is obtained corresponding to a toxic endpoint of 0.00081 mg/L.
The alternative release scenario for Chlorine involves a release from the Phosgene Production Plant of 19560 lb. of liquid Chlorine. Toxic liquid is assumed to be released to form a 1-cm deep pool from which evaporation takes place. The entire pool is estimated to have evaporated after 10 minutes. The release is also assumed to be controlled by excess flow valve(s), firewater monitor(s), and emergency shutdown system(s). These active mitigation systems have the effect of limiting the release to a 10-minute duration. Under neutral weather conditions, the maximum distance to the toxic endpoint of 0.0087 mg/L of Chlorin
e is 6.4 miles.
The alternative release scenario for Phosgene [Carbonic dichloride] involves a release from Polymeric MDI Production of 1635 lb. of phosgene gas. The release is also assumed to be controlled by deluge system(s), scrubber(s), emergency shutdown system(s) and steam curtain. These active mitigation systems have the effect of stopping the release in ten minutes and suppressing the released vapors. Under neutral weather conditions, the maximum distance to the toxic endpoint of 0.00081 mg/L of Phosgene [Carbonic dichloride] is 4.9 miles.
The alternative release scenario for Formaldehyde (solution) involves a release from Polymeric MDI Production. The scenario involves the release of 11440 lb. of 50% Formaldehyde solution from a broken transfer hose. Toxic liquid is assumed to be released to form a 1-cm deep pool from which evaporation takes place. The entire pool is estimated to have evaporated after 10 minutes. Passive mitigation controls such as dike(s) and sumps(
s) are taken into account to calculate the scenario, having the effect of reducing the surface area of the liquid pool. The release is also assumed to be controlled by excess flow valve(s) and emergency shutdown system(s). These active mitigation systems have the effect of stopping the release after ten minutes. Under neutral weather conditions, the maximum distance to the toxic endpoint of 0.012 mg/L of Formaldehyde (solution) is 1.1 miles.
The alternative release scenario for Ammonia (anhydrous) involves a release from Polymeric MDI Production. The scenario involves the release of 4500 lb. of anhydrous ammonia mixed with steam as part of a steam and ammonia curtain activated for 30 minutes to mitigate a release of phosgene gas. Under neutral weather conditions, the maximum distance to the toxic endpoint of 0.14 mg/L of Ammonia (anhydrous) is 0.16 miles.
The alternative release scenario for Methyl or Propyl Chloroformates involves a release from Chloroformate Production of 11,2
50 lbs. of 100% Methyl or Propyl Chloroformate liquid from a broken one inch pipe. Toxic liquid is assumed to be released to form a 1-cm deep pool from which evaporation takes place. The entire pool is estimated to be covered with foam after 15 minutes. Passive mitigation controls such as dike(s) and sumps(s) are taken into account to calculate the scenario, having the effect of reducing the surface area of the liquid pool. The release is also assumed to be controlled by emergency shutdown system(s). These active mitigation systems have the effect of stopping the release after 15 minutes. Under neutral weather conditions, the maximum distance to the toxic endpoint of 0.0019 mg/L of Methyl Chloroformate is 1.4 miles. In addition, the maximum distance to the toxic endpoint of 0.010 mg/L of Methyl Chloroformate is 0.68 miles.
4. The General Accidental Release Prevention Program and the Chemical-Specific Prevention Steps
The La Porte Site has taken all the necessary steps to c
omply with the accidental release prevention requirements set out under 40 CFR part 68 of the EPA. This facility was designed and constructed in accordance with Dow Loss Prevention Principles and Dow Engineering Standards. The following sections briefly describe the elements of the release prevention program that is in place at the La Porte site.
Process Safety Information
The La Porte Site maintains a detailed record of safety information that describes the chemical hazards, operating parameters and equipment designs associated with all processes. Some examples of the records described are material safety data sheets, equipment specification sheets, and reactive chemical compatibility grids.
Process Hazard Analysis
The La Porte Site 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 the Dow comprehensive safety and loss prevention internal audit which
includes the use of the Dow Fire and Exposure Index, the Dow Chemical Exposure Index, and the 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 three years. Any findings related to the hazard analysis are addressed in a timely manner. The most recent PHA/update was performed on 04/18/2000.
For the purposes of safely conducting activities within our covered processes, the La Porte Site 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 La Porte Site has a comprehensive training program in place to en
sure that employees who are operating processes are competent in the operating procedures associated with these processes. Refresher training is provided at least every three years and more frequently as needed.
The La Porte Site 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 operations are carried out by qualified personnel with training in maintenance practices. Furthermore, these personnel are offered specialized training as needed. Any 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 La Porte Site to manage changes in process chemicals, technology, equipment and procedures. The most recent revi
ew/revision of maintenance procedures was performed on 11/01/2000. 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 La Porte Site. The most recent review was performed on 04/18/2000. 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 La Porte Site 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 09/30/1997. These audits are carried out at least every three years and any corrective actions requi
red as a result of the audits are undertaken in a safe and prompt manner.
The La Porte Site 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 five years.
The La Porte Site 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.
On occasion, 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 La Porte Site has a strict policy of informing contractors of known potential hazards related the contractor's work and the processes. Contractors are also informed of all the procedures for emergency response should an accidental release of a regulated substance occur. Contractors are also required to inform the Dow Chemical Company of any hazards they may introduce at the site
5. Five-year Accident History
La Porte Site has had an excellent record of preventing accidental releases over the last five years. Due to our stringent release prevention policies, there have been no accidental releases as defined by the RMP rule of regulated substances during this period.
6. Emergency Response Plan
The La Porte Site carries 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 require a modified emergency response.
La Porte and Deer Park are the Local Emergency Planning Committees (LEPC) with which our emergency plan has been coordinated and verified.
7. Planned Changes to Improve Safety
The effectiveness of the steam ammonia curtain has been evaluated and found to be ineffective. The anhydrous ammonia will be removed from the site i