Dover Chemical Corporation - Executive Summary
The Dover Chemical Corporation plant manufactures a variety of fire retardant and surfactant chemicals for customers who make consumer and commercial products. Certain raw materials and by-products are toxic chemicals that are regulated under EPA Risk Management Programs regulations that can be hazardous if released to the air in large quantities.
Dover Chemical Corporation is committed to protecting its employees, the public, and the environment from any accidental releases of hazardous materials used at its facilities. We have implemented safety, environmental protection, and risk management programs to prevent hazardous materials releases. If there is an emergency, we will immediately mobilize our emergency response team to contain and minimize the effect of the release and notify the public of any actions necessary to ensure public protection, through local emergency management agencies.
Worst-Case Release Scenario
Dover Chemical has conducted an offsite consequence analysis i
ncluding a worst-case release scenario. As required by the EPA RMP regulations, the worst-case scenario is defined as a release of the chemical with the greatest potential impact distance where the entire contents of the largest vessel or container is released within ten-minutes. Chlorine is the worst-case chemical for this facility. The regulations require assuming worst-case wind speed and atmospheric conditions that result in the greatest projected impact distance.
For the offsite consequence analyses, the "endpoint" concentration is defined by the Emergency Response Planning Guideline (ERPG-2) values developed by the American Industrial Hygiene Association (AIHA) or, if not available, other values set by EPA. AIHA defines the ERPG-2 value as, "the maximum airborne concentration below which it is believed that nearly all individuals could be exposed for up to one hour without experiencing or developing irreversible or other serious health effects or symptoms that could impair an
individual's ability to take protective action." The endpoint (ERPG-2 value) established for chlorine is 0.0087 mg/L (3 ppm).
For the urban setting of the Dover area, the distance to the endpoint concentration obtained for the worst-case release extends offsite into residential and commercial areas in and around the City of Dover. This distance was obtained from the dispersion modeling software Areal Locations of Hazardous Atmospheres Version 5.2.1 (ALOHA). ALOHA was developed through a joint effort of the Environmental Protection Agency and the National Oceanic and Atmospheric Administration (NOAA) as a tool for emergency responders and emergency planning in assessing potential dispersions of hazardous materials. ALOHA does not predict distances beyond 6 miles because NOAA does not consider predictions beyond 6 miles to be reliable due to the likelihood of variable terrain and wind conditions.
A major release of the magnitude represented by this worst-case scenario is extremely un
likely because of the robust design of transport containers (they are designed to withstand transportation mishaps) and the rigorous maintenance and prevention programs in place for transport containers and at our facility. In fact, release reporting databases and industry experience suggest that the worst-case release scenario as defined in the RMP regulations is so unlikely that it should not be used as the basis for emergency planning. A more reasonable potential release scenario for emergency planning is presented in "The alternative release scenario(s)" section below.
Alternative Release Scenario
"Credible worst-case" scenarios were selected as the alternative release scenarios. These scenarios assume that there is a major leak in the transfer hose for each chemical. For chlorine, the transport container has an excess flow valve designed to automatically stop the release of chlorine if there is a transfer hose failure. We conservatively assumed that there was a serious leak at
just below the flow rate designed to automatically shut off the flow and that the release lasted for ten minutes.
The truck unloading and loading of the remaining chemicals is attended by operators and truck drivers and shutoff valves can be used to stop the release. These scenarios conservatively assume that the liquid release will continue at the normal transfer rate for ten minutes where the shutoff valve is manually operated and for five minutes where there is an automatic shutoff valve activated by touching a button.
ALOHA was then used to estimate the rate of gas release from the liquid pool for pure liquid chemicals. ALOHA results predict a high initial rate of evaporation and then a declining rate due to cooling of the liquid. On the submittal, the "Maximum Average Sustained Release Rate (averaged over a minute or more)" was reported as the release rate instead of the average release rate because the maximum rate generally has the greatest affect on the distance to endpoint
The EPA RMP Offsite Consequence Analysis Guidance document's equations were used to estimate gas release from the liquid pool for mixtures (i.e., hydrochloric acid). ALOHA was then used to estimate the distance to endpoint concentration for all cases.
The results of the process hazard analysis (PHA) and the facility's operating history suggest that even this credible worst-case is extremely unlikely to occur, but it can help support emergency planning.
The potential distances to the endpoint concentration for these alternate release scenarios also extend offsite into residential and commercial areas. As with the worst-case scenario, actual distances and directions vary with terrain and weather conditions.
Accidental Release Prevention Steps
To ensure a worst-case or alternative release scenario does not occur, our facility maintains a release prevention program with the primary focus of protecting plant employees and the public from the hazards associated with an accident or r
elease involving a hazardous chemical. The prevention program has twelve elements designed to meet both EPA and OSHA Process Safety Management requirements.
Our facility is committed to personnel safety, public safety, continued reliable operation and regulatory compliance. Based on this commitment, the Vice President for Environmental Affairs and the Vice President of Manufacturing have assumed responsibility for the development and implementation of the Risk Management Program. We have also clearly defined accountability and responsibility for each of the twelve prevention program elements.
Our prevention measures include the use of:
- chlorine and hydrochloric acid detectors and alarms to rapidly alert operators to any problems;
- operator attended truck loading and unloading operations;
- secondary containment around tanks;
- water filled secondary containment for bromine that will effectively suppress vaporization in the event of a spill or leak;
- process safety information
to document the safe process design;
- process hazards analyses to evaluate the chemical and process hazards;
- operating procedures to ensure that the system is operated safely;
- maintenance, inspection and testing to ensure that the system is maintained according to applicable standards and manufacturer's recommendations;
- training, hot work permits, contractor safety and employee participation programs to ensure that all employees and contractors working on and around the processes are aware of the hazards, can perform their job duties safely and know the actions to be taken in an emergency;
- management of change and pre-startup safety reviews to ensure that changes are documented, analyzed and kept within the design basis;
- incident investigation procedure to investigate each incident and "near misses" to determine root causes and make needed safety improvements; and
- periodic compliance audits to ensure that our programs are working as they should to protect both employees a
nd the public.
Five-Year Accident History
Within the past five years, the Dover Chemical facility has had one accident due to a release of RMP regulated chemicals that met EPA regulatory criteria (i.e., an accident that resulted in injuries, property damage or any offsite impacts). The release was very small, probably less than one pound of hydrogen chloride vapor, and only affected an operator that was working next to the equipment. There was no potential for offsite effects because of the small size of the release.
In the event that a chemical release does occur, Dover Chemical has an emergency response program that includes trained onsite emergency responders and coordination with the City of Dover Fire Department and the Local Emergency Planning Committee. If an emergency did occur, plant personnel will immediately activate our emergency response team to contain and minimize the effect of the release and notify the public of any actions necessary to ensure pu
blic protection, through local emergency management agencies.
Maintaining A Safe Operation
Dover Chemical continually works to safely manage the hazards of chemicals to protect employees and the community we serve. The Risk Management Program will be maintained to reduce the risk of accidental releases and each year we will conduct training, review procedures, maintain the equipment and follow safe work practices. Periodically, we will audit our program, review our Process Hazard Analyses and coordinate with the community emergency response organizations.
Planned changes to improve safety
We have recently begun testing a remotely activated shutoff valve for the chlorine rail cars that can be used to more rapidly shut down flow in the event of an unloading hose release. We will be taking the following additional steps in the future:
- installing automatic shutoff valves on all chlorine rail cars;
- installing additional chlorine process area monitors; and
- installing a video
camera on the rail car operation to assist the operator in making a rapid decision on whether to shut the automatic valve.
We will also be assessing further safety enhancements to the facility on an ongoing basis over the next few years.