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Timestamp: 2019-11-12 11:21:15
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HoltraChem Manufacturing Company - Executive Summary
HoltraChem Manufacturing Company owns and operates a plant in Riegelwood, North Carolina, which is subject to U.S. Environmental Protection Agency (EPA) regulations governing Accidental Release Prevention (ARP) Requirements: Risk Management Programs under Section 112(r) of the Clean Air Act (40 CFR Part 68). This Risk Management Plan (RMP) has been developed in accordance with the requirements specified under 40 CFR Part 68, Subpart G. The RMP certifies that HoltraChem Manufacturing Company has instituted a Risk Management Program at the Riegelwood, North Carolina, facility that is in compliance with U.S. EPA ARP requirements.
The RMP includes an Executive Summary and Data Elements. This document identifies the applicable corporate policies and risk management systems, including comprehensive accident prevention and emergency response programs. In addition, th
is RMP identifies a set of worst case and alternative release scenarios, the potential off-site consequences of those releases, and the facility's five year accidental release history. This RMP certifies that prevention and emergency response programs are in place so as to minimize risks to workers and the potentially affected public.
1.0 HOLTRACHEM MANUFACTURING COMPANY ACCIDENTAL RELEASE AND
HoltraChem Manufacturing Company recognizes its legal and moral responsibilities to manage its business in the most efficient and effective manner to ensure protection and enhancements of our nature environment. HoltraChem, and all of its associates, commit to continuously improving our understanding of plant's processes and products and their interaction with the environment. We will perform our day-to-day activities with continuous awareness of and concerns for the environment. HoltraChem is committed to saving and enha
ncing the quality of the waters, lands, and air of our communities and of the State for the benefit of the current as well as future generations
HoltraChem maintains knowledge and understanding of all applicable federal, state, and local environmental laws and regulations and implements programs to assure compliance with them. Where, in the opinion of HoltraChem, the existing laws are not adequate to assure protection of the environment, we will establish our own environmental standards through the application of sound science.
HoltraChem works diligently to prevent all releases to the air, land, and waters, and to minimize the amount and toxicity of wastes generated. This commitment is communicated to our associates, vendors, customers, and the public. HoltraChem strives to continuously improve our commitment to the environment and to the people of the state.
HoltraChem Manufacturing Company has developed a management system to implement and mainta
in compliance with the Accidental Release Prevention (ARP) and related chemical safety and emergency response programs. This management system identifies lines of responsibility for the entire program and each of its key elements, as illustrated in Figure 1-1.
Figure 1-1 Organization Chart
OFF-SITE HAZARD ASSESSMENT PSM PROGRAM EMERGENCY RESPONSE PROGRAM
Safety & Env. Manager Safety & Env. Manager Safety & Env. Manager
Process Engineer Maintenance Superintendent
The Holtrachem Manufacturing Company manufactures chlorine, commercial bleach, causti
c soda, and hydrochloric acid at the Riegelwood, NC, facility in a single integrated process. The raw materials utilized by the plant include water, salt, and electricity. Chlorine is the only chemical manufactured and stored at the facility that is present at or above threshold amounts for regulated substances and are regulated under 40 CFR Part 68.
The EPA Risk Management Regulation identifies three levels of requirements for industrial processes. Program 1 can be applied to any process which has not had a "significant" release of a regulated substance over the five year period prior to the June 1999 compliance date and for which the worst-case release does not affect "public receptors" (e.g., residences, parks and recreation areas, commercial/industrial facility, hospitals). Program 2 applies to any process that is ineligible for Program 1 and is not subject to Program 3. Program 3 applies to all processes, such as those present at the Holtrachem facility, that are subject to t
he Occupational Safety and Health Administration (OSHA) Process Safety Management Standard (PSM). The Holtrachem Accident Prevention Program elements are adopted directly from the compliance program for the PSM standard, consistent with the Level 3 RMP Program requirements for this Holtrachem facility under 40 CFR Part 68. Program 3 related information is included in the Data Elements section of the Risk Management Plan.
2.1 Chlorine Production System
Chlorine is produced at the Holtrachem Riegelwood facility as part of an integrated process using electrolysis. Ultra-purified brine is pumped through electrolyzers and chlorine is stripped off, under vacuum. It is then de-watered using sulfuric acid in a gas cooler. The brine is neutralized, has a reducing agent added to react residual chlorine, and is recycled. Meanwhile, the electrolyzers produce caustic soda, which is concentrated through evaporation, to desired strength. Chlorine is also taken off in a side stream and combined wi
th hydrogen in a special burner, to produce hydrochloric acid.
For the purposes of developing and maintaining adequate Risk Management Plans, the EPA has defined in its governing rules and guidance a series of modeling methods and assumptions which are to be used as administrative guides for planning purposes. In order to standardize and simplify the many factors that can potentially occur in an accidental release situation, some of these assumptions may not take into account the available preventive measures or mitigation methods that could diminish or even eliminate the implied risks that are suggested by "worst-case" analyses. For that reason, both the results for the standardized "worse-cases" defined by the EPA methods and a set of alternative cases which are believed by Holtrachem to more realistically represent situations that may possibly, but rarely, occur within the lifetime of the facility are also presented. The sections of the Risk Management P
lan which discuss both worst-case, and alternative cases, are meant to provide the data necessary to develop and evaluate possible improvements in the overall safety programs of the Holtrachem RMP program.
The worst-case release scenario, as defined by 40 CFR Part 68, is a sudden release of the maximum amount of a stored regulated substance from a single vessel, regardless of whether several vessels are interconnected. For toxic gases such as Cl2 stored at ambient temperatures it is assumed that the release occurs over a 10-minute period. Only passive mitigation (e.g., dikes, enclosures) and administrative controls may be accounted for in the evaluation.
EPA has established "toxic endpoints" for various chemicals based on the American Industrial Hygiene Association (ACGIH) Emergency Response Planning Guideline, Level 2 (ERPG-2), which protects individuals from health-threatening or escape-impairing injury. The ERPG-2 is defined as:
Given that the worst-case is a 10-minute release duration with a 10-minute concentration averaging time, the actual hazard zone is typically overestimated by the ERPG-2. Within such a time period there are a number of emergency measures that can reduce or eliminate exposures to levels this high for an interval much shorter than an hour.
Under Section 68.22 (e), the RMP rule identifies "surface roughness" as a parameter to be specified in the hazard assessment. The surface roughness affects the amount of dispersion that occurs within a released plume and influences the distance to toxic endpoint. The surface roughness used in determining the distance to toxic endpoint should be characteristic of the tra
nsport path of the plume from the release point to the endpoint distance. 'Urban' surface roughness indicates areas where there are many obstacles, such as industrial buildings or trees. 'Rural' indicates that there are no buildings in the immediate vicinity of a facility and that the terrain is generally flat and unobstructed.
In the immediate vicinity of the Holtrachem Riegelwood facility, the aerodynamic surface roughness is clearly 'urban' in nature, whereas at greater distances, the surface roughness is more 'rural'. In order to report the most conservative 'distance to toxic endpoint' estimates in the Risk Management Plan, Holtrachem has elected to model the worst-case release scenario assuming 'rural' surface conditions. However, it should be noted that under actual conditions, plume dispersion would be enhanced by the 'urban' type surfaces located near the facility, and result in shorter distances to toxic endpoint.
The EPA's RMP Off-site Consequence Analysis Guidance (19
99 Revised OCAG) was utilized to determine distance to toxic endpoint values for the worst-case release scenarios. The OCAG guidance lists a number of refined dispersion models that are also available for off-site hazard assessment applications for risk management programs. The molecular weight of chlorine is substantially greater than the ambient air. For this reason, concentrated plumes of this substance resulting from accidental releases often display heavy-gas behavior. In such a case, near-field dispersion is dominated by gravitational slumping of the plume and entrainment of air at the plume-air interface. One of the models listed in the OCAG commonly used for heavy-gas releases is SLAB. SLAB, developed by Lawrence Livermore Laboratory, can be utilized to model scenarios that are not directly addressed in the 1999 Revised OCAG. For these reasons, the OCAG was used to determine the endpoint distance for the worst case release, while SLAB was used to determine the endpoint
distances for the more complex alternative release scenarios.
In accordance with 40 CFR Part 68, the worst-case modeling is conducted assuming a very stable atmosphere with limited dispersion (F stability and 1.5 m/sec wind speed). Analysis of three years of meteorological data from the National Weather Service in Wilmington, NC, indicates that these dispersion conditions occasionally occur in the area. The windrose based on the three year period 1989-1991 indicates that the most predominant directions of transport are to the northeast and southwest.
The toxic endpoint for Cl2 is 0.0087 mg/L. Since the resulting planning zone predicted for the "worst-case" Cl2 toxic release potentially affects public receptors, regulated processes at the Holtrachem Riegelwood facility are subject to Program 3 requirements. 40 CFR Part 68 requires that the substance with the largest distance to toxic endpoint be reported in the Worst-Case Release section of the Risk Management Plan.
3.1.1 Worst-
Case Release: Chlorine
The worst-case scenario for the Riegelwood facility consists of a 10-minute gaseous ground-level release of 180,000 lbs of stored Cl2, dispersed under atmospheric conditions of F stability and 1.5 m/sec wind speed. A gaseous release of this magnitude over such a short time-span is physically impossible because the amount of heat energy required to so rapidly vaporize the liquid Cl2 would not be available. Even if the storage tank were to breach, liquid Cl2 would spill to the ground in a boiling pool. If a hole were to form in the vapor space of the storage tank, the flashing vapor in the tank would cause the tank to auto-refrigerate, thereby gradually reducing the release rate with time. The selection of the worst-case release for Cl2 should, therefore, be viewed as a regulatory necessity, rather than a realistic representation of a worst-case release event.
The modeling results indicated that under 'rural' surface conditions the worst-case Cl2 release woul
d result in a distance to toxic endpoint of greater than 25 miles. The worst-case impact zone encompasses a resident population of approximately 160,000, based on the 1990 Federal Census, and estimated by applying EPA's Landview III program. Public receptors were identified using 1:24,000 scale U.S.G.S maps, supplemented with comprehensive maps of the local Eddyville area (Rand McNally, 1990, and DeLorme Street Atlas USA, Version 5). The potential worst-case hazard zone includes schools, hospitals, prisons, public recreation areas, and industrial/commercial areas. Several environmental receptors (defined as National or State parks, forests, officially designated wildlife sanctuaries, preserves, refuges, and federal wilderness areas) are also located within the worst-case impact zone. The closest environmental receptor is the Moores Creek National Park.
3.2 Alternative Releases of Toxic Substances
Alternative releases are intended to represent release scenarios that have a gr
eater likelihood of occurrence than a worst-case release. Alternative releases do not necessarily represent the types of releases that the PSM hazards analysis and/or accident history indicate would be most frequent, but rather a release that is somewhat more likely than the worst-case release and that generally still has the potential to affect off-site receptors. In accordance with the EPA's OCAG, a single alternative release scenario is reported for each regulated substance.
Holtrachem performed a thorough review of the facility utilizing engineering plans, operational experience, and maintenance records, in order to determine alternative release scenarios that could potentially result in off-site impacts. Each scenario was evaluated and the scenarios most likely to occur and to result in off-site impacts were selected for modeling. In order to determine the most conservative off-site consequence estimates, Holtrachem has chosen to include in the Risk Management Plan the alternat
ive release scenarios that resulted in the greatest toxic endpoint distance for each regulated substance.
In accordance with the RMP rule, alternative releases are modeled under typical (rather than worst-case) dispersion conditions. The EPA OCAG default dispersion conditions are neutral atmosphere, with dispersion neither enhanced nor limited (D stability and 3 m/sec wind speed). A review of climatological data for Wilmington, NC, confirmed that these conditions are typical of the area and therefore are suitable for the evaluation of alternative releases. Unlike the worst-case release (for which an instantaneous spill or 10-minute ground-level gas release is assumed), alternative scenarios can account for the actual release configuration, and account for both active and passive mitigation.
Alternative dispersion modeling was conducted using the SLAB dense gas dispersion model. Because the surface roughness in the immediate vicinity of the Riegelwood facility is urban in nature and
alternative releases typically result in relatively short endpoint distances, an urban surface roughness value was utilized in the alternative release modeling.
The alternative Cl2 release scenario that would result in the greatest off-site impact involves a release from the Cl2 scrubber due to a power failure. The modeling indicated that Cl2 would be released at a rate of 1000 lbs/min. It is conservatively assumed that the Cl2 would then be dispersed as a heavy gas. Holtrachem has estimated that it would take an operator approximately 10 minutes to respond and shutdown the flow of Cl2, resulting in a total release of 10,000 lbs. This alternative Cl2 release scenario is expected to be more representative of the maximum anticipated release at the facility than the "worst-case".
The SLAB modeling indicates that under urban conditions, the distance to toxic endpoint would be 3.8 miles. The hazard impact zone encompasses an estimated residential population of app
roximately 1400 persons, based on the 1990 Federal Census, and estimated in conjunction with EPA's Landview III database program. Public receptors in the alternative impact zone include public recreation areas, schools, and industrial/commercial areas. No environmental receptors, as defined by the regulation, would be affected.
4.0 ACCIDENT PREVENTION PROGRAM
Some processes subject to the Risk Management Regulation are also subject to Occupational Safety and Health Administration (OSHA) Process Safety Management Standard (PSM). PSM governs the same processes and regulated substances at the site that are subject to 40 CFR Part 68. Holtrachem has a PSM program at the Riegelwood plant that includes the following elements:
- Employee Training and Participation
In conjunction with the current RMP and PSM programs in place at the Riegelwood plant, there is a standard management practice that requires immediate internal reporting of unusual events, including those in which any abnormal emission of regulated chemicals is observed or suspected. The incident information is reviewed by supervisory staff and a determination is made as to whether a reportable quantity on any chemical listed as requiring reports to regulatory authorities is involved. If so, the appropriate authorities are promptly notified.
During the past 5 years (June 1994 to June 1999), there have been no accidents involving any RMP regulated substance that qualifies for reporting under 40 CFR Part 68.
Emergency situations at HoltraChem's Riegelwood plant can include fire, chemical release or spill, explosion, bomb threat, and weather emergencies. The plant
has three basic documents which address forseeable emergency situations at the facility and provide appropriate hazard and emergency preparedness information to employees, contractors, emergency response personnel, and the community. The first of these, mindful of the ongoing risks presented by weather emergencies such as tornadoes, is an Emergency Action Plan. This is designed to protect both the plant's operational integrity and the safety of its workers and neighbors from the consequences of weather emergencies. In regards to chemical releases, HoltraChem has a command structure and specific procedures to handle the unlikely event of a chemical emergency. These procedures cover the following:
* Escape routes for non-involved personnel
* Accounting for persons at the facility
* Procedures for various weather emergencies
* Ignition sources and control procedures
A separate document, the Emergency Re
sponse and Fire Protection Plan, is intended to enable a more aggressive response to a release. Certain HoltraChem employees are trained in HAZWOPER, and the Emergency Response and Fire Protection Plan cites, among other hazard scenarios, releases of chlorine from tank cars, tank car loading lines, carrier outlet lines and scrubber feed lines. This Plan has a mechanism for regulatory agency contacts, including the local LEPC.
HoltraChem has available the Acme-Delco-Riegelwood Fire and Rescue Squad (Riegelwood, NC) to offer paramedical assistance and transportation to the New Hanover Memorial Hospital and Columbus County Hospitals. In addition, certain plant personnel have the capability to perform basic first aid and CPR.
Holtrachem's Riegelwood plant, under the recent RMP program, as well as its existing PSM and earlier SARA Title III Community Right-to-Know Act compliance programs has organized its management system to effectively addr
ess hazards and potential risks. Both the advanced planning aspects of process design, operating procedures, and emergency preparedness, and the operational elements of system maintenance, safe operating practices and ongoing personnel training are necessary to support a continual improvement in facility safety. These programs are thoroughly documented so that information about the safe handling of chemicals present at the facility is available to all employees, and can be readily accessed by emergency response team staff and the Incident Commander. This is especially important when questions arise from public safety officials regarding potential risks to the community. All of these features of the RMP and the integrated risk management program at the Riegelwood plant are intended to protect both the safety of employees and the community.
These programs which involve operating procedures for the new membrane cell process have not yet been tested, but only because this new portion o
f the facility is not yet operational. This includes relevant management of change (MOC) and pre-startup safety review (PSSR) procedures.
Holtrachem Riegelwood's safety program incorporates audits, inspections, and on-going evaluations of in-plant safety and program effectiveness. The information gathered is evaluated and improvements that are identified are merged into the program.
HoltraChem Manufacturing Co. Riegelwood RMP Executive Summary June 1999