IBP, inc. - Executive Summary
EXECUTIVE SUMMARY |
Accident Release Prevention Program and Emergency Response Policy
It is the policy of the IBP, inc. (IBP) Dakota City, Nebraska facility management to implement the requirements of this Risk Management Program (RMP) in accordance with the USEPA regulations under 40 CFR Part 68 and with the corresponding regulations under OSHA's Process Safety Management (PSM) program. The objective is to minimize the risk of a release of a hazardous material and if a release occurs, to minimize the potential impact to IBP employees, the public and the environment. This objective will be accomplished by utilizing general good operating procedures, providing appropriate training to all employees, and coordinating response activities, as necessary, with the local emergency response providers. This plan covers all IBP owned activities at this facility.
IBP's management is committed to providing the resources necessary to implement this policy.
IBP operates a
cattle slaughter and processing facility and a hides tannery at this location. Cattle are trucked to the facility, slaughtered and fabricated. IBP operates rendering systems to produce gel bone, dried blood, low protein beef byproducts, tallow, and other rendered products. Support operations include a wastewater treatment system, truck repair facilities, cold storage, an analytical laboratory, and administrative offices.
Three chemicals are utilized or generated at the facility in sufficient quantities to be subject to the requirements of 40 CFR Part 68. These chemicals are chlorine, ammonia, and methane. Chlorine is used as a disinfectant and to treat wastewater, ammonia is used as a refrigerant throughout the facility, and methane is generated as an off-gas from the anaerobic lagoons in the wastewater treatment plant.
Worst-Case and Alternative-Release Scenarios
RMP regulations require that each facility identify worst-case and alternative case release scenarios. EPA has def
ined a worst-case release as the release of the entire contents of the largest vessel that contains a regulated substance in a 10-minute period. This release rate is then evaluated using modeling techniques and/or reference tables to define the distance to a specified endpoint (concentration or overpressure). The distance to the endpoint is affected by several factors including molecular weight, volatility, heat of combustion, and physical setting (urban or rural).
The alternative release scenario must be one that is more likely to occur than the worst-case scenario and that reaches an endpoint offsite, unless no such scenario exists. The alternative release scenario is also evaluated to define the distance to the specified endpoint.
Under 40 CFR 68 Subpart B ?68.22(e), the RMP rule identifies surface roughness as a parameter to be used in the hazard assessment to determine the physical setting of the site, urban or rural. "Urban means there are many obstacles in the immediate ar
ea; obstacles include buildings or trees. Rural means there are no buildings in the immediate area and the terrain is generally flat and unobstructed."
Due to the presence of trees, hills, and/or other structures in the immediate vicinity of the Dakota City, Nebraska facility, an urban dispersion environment was assumed.
The Dakota City, Nebraska facility has two separate ammonia refrigeration systems (Processing and Slaughter) and two identical chlorine systems (Main Plant and Wastewater Treatment Plant). The worst-case release area for the chlorine systems would contain the area impacted by the worst-case release for the Processing and Slaughter ammonia systems. Therefore, one worst-case toxic release was specified for the entire facility.
The Dakota City, Nebraska facility has a methane flare system from the covered anaerobic lagoons located at the Wastewater Treatment Plant.
The dispersion model applied to the worst-case and alternative chlorine release scenarios w
as the EPA-approved model, HGSYSTEM. HGSYSTEM is a consequence model that has seven distinct modules that are used to predict the potential ambient concentrations resulting from single (gas) and two-phase jet (gas and aerosol) releases from pressurized vessels, vapor releases, liquid spills and the subsequent evaporation of the spill pool. HGSYSTEM was selected for this application because of its flexibility in simulating the necessary release characteristics, plume dispersion (e.g., dense gas dispersion), and its capability of simulating the dispersion environment through which the plume travels (e.g., time varying meteorological conditions).
The worst-case release scenario for chlorine included a release of all the contents of the storage vessel (2,000 pounds) in a 10-minute period. This release translates to a release rate of 200 lbs/min. Other assumptions for the worst-case chlorine analysis include the chlorine is a liquefied gas; the 1-ton cylinder is not diked; no passive m
itigation system (including buildings) are in place; the nearfield dispersion environment is characterized as urban; 10-minute averaging period; the windspeed is 1.5 meters/sec and the atmospheric stability is classified as F (stable). The results of the worst-case assessment for chlorine show that the regulatory defined endpoint of 3.0 ppm is found to occur at a distance of 3.23 miles (5.2 kilometers) from the release point.
The selected alternative-release scenario for the chlorine system is a release resulting from a fusible plug failure that leads to the release of the entire contents of the 1-ton chlorine cylinder. Based on information in the Chlorine Institute Chlorine Handbook, the release rate of vaporized chlorine from the fusible plug opening is an average of 14.6 lbs/min. Based on the calculated release rate of 14.6 lbs/min, the duration of a 2,000-pound release is 136 minutes. The model assumes no active or passive mitigation measures are currently in place. The meteo
rological data used for this alternative release scenario was a wind speed of 3 meter/sec, an atmospheric stability classification of D (neutral stability), and an urban dispersion environment in the nearfield. The results of the alternative-release scenario for a chlorine release indicates that the endpoint of 3.0 ppm is reached at a downwind distance of 0.31 miles (500 meters) from the release point.
The data provided in the document "Model Risk Management Program and Plan for Ammonia Refrigeration" (May 1996) was used to estimate the toxic endpoint distance for the worst-case and alternative ammonia release scenarios. The EPA's "RMP Off-site Consequence Analysis Guidance" (May 1996) was not used to determine the toxic endpoint since it classifies ammonia as a neutrally buoyant gas. Since the worst-case ammonia release would involve liquid and would come from a pressurized system containing liquid, the released gas should be classified as a dense gas (a result of evapora
tive cooling). The ammonia refrigeration document provides calculated endpoint distances for typical meteorological conditions.
The worst-case release scenario for an anhydrous ammonia release included a release of all the contents of the new high pressure receiver number in a 10-minute period (per EPA guidelines). This release translates to a release of 57,708 pounds of ammonia in 10 minutes or 5,770.8 lbs/min. Other assumptions included in the worst-case assessment are: the ammonia is a liquefied gas; the new high pressure receiver is not diked; the release does not take place indoors; the nearfield dispersion environment is characterized as urban; 10-minute averaging period; the wind speed is 1.5 meters/sec and the atmospheric stability is classified as F (stable). The results of the worst-case assessment for ammonia show that the plume must travel 2.68 miles (4.31 kilometers) before dispersing to the endpoint concentration of 201 ppm.
The selected alternative-release scenario
for the ammonia systems is a release from a relief valve due to overpressure of a compressor unit. The largest relief valve in the system was used in this scenario. The largest relief valve has a relief rate of 90 pounds of air per minute. As a matter of convention, the specified release rate of any relief valve is always in pounds of air per minute. The release rate of 90 pounds of air per minute correlates to a release rate of 64.5pounds of ammonia vapor per minute. This release rate was applied to a release from the ammonia header on top of the building.
The ammonia refrigeration document provides calculated endpoint distances for typical meteorological conditions (3 m/s wind speed, D atmospheric stability, 50% relative humidity). It has been determined, through a review of IBP's operational history, that the total release would likely be 500 pounds of ammonia. Based on the release rate of 64.5 lbs/min, the duration for a 500-pound release is 7.8 minutes. Other assumptions
include that no active or passive mitigation measures are currently in place and an urban dispersion environment in the nearfield. The results of the alternative-release scenario for an ammonia release indicate that the endpoint concentration of 201 ppm is reached at 0.073 miles (117 meters) from the release point.
The wastewater treatment facility operates two identical existing covered anaerobic lagoons and three identical new covered anaerobic lagoons. The worst-case release scenario for methane is defined as a release of all the contents of the largest covered anaerobic lagoon (36,570 pounds). For the worst-case release of methane, the release rate is not considered. The total quantity of the methane is assumed to form a vapor cloud. The entire contents of the cloud are assumed to be within the flammability limits, and the cloud is assumed to explode. For the worst-case analysis, 10% of the flammable vapor in the cloud is assumed to participate in the explosion (i.
e., the yield factor is 0.10). Consequence algorithms were used to determine the endpoint at an overpressure level of one pound per square inch (psi). Other assumptions for the worst-case methane analysis include that the methane is a flammable gas; no passive mitigation system is in place; the nearfield dispersion environment is characterized as urban; the wind speed is 1.5 meters/sec and the atmospheric stability is classified as F (stable). The results of the worst-case assessment for methane show that the 1-psi overpressure endpoint occurs at a distance of 0.28 miles (445 meters) from the release point.
The selected alternative-release scenario for the methane system is a release resulting an inspection hatch (18-inch diameter port) being accidentally left open through human error. Based on the operating pressure and opening of the hatch a release rate of methane is 240 pounds per minute was calculated. To estimate the impact distance for this alternative-release scenario, a
vapor cloud fire was assumed to occur. The distance to the Lower Flammability Limit (LFL) represents the maximum distance at which the radiant heat effects of a vapor cloud fire might have serious consequences. The LFL for methane is 33 mg/L (EPA guidance document). In accordance with USEPA guidance, the modeling assumptions were that methane is a buoyant gas and an urban dispersion environment exists in the nearfield. According to the EPA guidance document, the endpoint distance for release rate of less than 5,000 lbs/min and a LFL between 30 and 35 mg/L is less than 0.06 miles (95 meters) from the release point.
General Accidental Release Prevention Program and Chemical Specific Prevention Steps
The Dakota City, Nebraska facility is governed by a set of OSHA and USEPA regulations that require planning and facility activities intended to prevent a release of hazardous material, or if a release inadvertently occurs, to minimize the consequences of a release to the employees of th
e facility, the public and to the environment. These regulations include:
* 40 CFR Part 68, Accidental Release Prevention
* 40 CFR Part 112, Spill Prevention, Control and Countermeasure
* 40 CFR Part 264, Hazardous Waste Contingency Plan
* 29 CFR Part 119, Process Safety Management
* 40 CFR Part 302, Emergency Planning and Community Right-to-Know Act (EPCRA)
The key concepts in IBP's release prevention program are employee participation, appropriate design and maintenance of equipment, and appropriate training of all employees. IBP has developed and documented these elements in their process safety management plan (PSM). The PSM plan is incorporated with this document by reference.
Employee participation in the release prevention program is encouraged and supported by IBP management. Key personnel are responsible for conducting and implementing the findings from the Process Hazard Analysis (PHA) for the ammonia and chlorine systems, and for conducting the process safety revi
ew for the methane system. IBP employees are also members of the facility emergency response team.
IBP policy is to construct all new equipment, systems, and facilities to ensure the appropriate safety and release prevention systems are included from the beginning of each project. IBP maintains a computerized program of maintenance activities to ensure that key systems are maintained appropriately to minimize the risk of a release.
IBP is committed to providing appropriate training to all employees regarding safety procedures. Each new employee is provided comprehensive safety training during their initial orientation for the facility. In addition, IBP conducts regularly scheduled safety training for all employees each year. Additional training is provided to maintenance personnel for the systems they are responsible for. Members of IBP's emergency response team receive semiannual training to ensure that response actions are promptly and safely completed.
Five Year Accident Hi
IBP has not had a release of chlorine, or methane from the Dakota City, Nebraska facility that has affected the public or the environment.
Between May 1997 and May 1998, IBP had two releases of ammonia from the Dakota City, Nebraska facility that resulted in two OSHA recordable injuries. Neither of these releases affected the public or the environment. Both releases were small and did not require an incident investigation. Therefore, IBP does not have records of the time and duration of the releases or the release quantities of these releases. IBP has assumed, after reasonable inquiry, the time of the incident is 12:00 PM, lasted one minute, and released one pound of ammonia.
Emergency Response Program
IBP has personnel trained in emergency response at the facility 24 hours per day, seven days per week. These personnel receive semiannual training on emergency procedures and response techniques.
IBP does not have emergency response capability on site to respond to a meth
ane emergency. It is IBP's policy to contact off-site emergency responders for assistance in the event of an accidental release of methane.
IBP's employees will attempt to extinguish small fires with fire extinguishers if they have been properly trained. IBP's employees, trained in the safe operation of the methane system, will close manual shutoff valves to terminate the flow of methane if the valves can be safely approached. For all other scenarios, IBP's employees will evacuate the area and allow off-site responders to respond to the emergency.
IBP has met with the local fire department to review the methane system and to establish coordination and communication procedures.
Planned Changes to Improve Safety
IBP completes a thorough review of the ammonia systems, chlorine systems, and the methane flare system each time a design change is implemented. IBP is committed to using these methods to identify and implement ways to improve the safety of these systems.