Kimberly-Clark Everett Mill - Executive Summary |
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SECTION 112(r) RISK MANAGEMENT PLAN KIMBERLY-CLARK TISSUE COMPANY EVERETT, WASHINGTON EXECUTIVE SUMMARY Introduction The attached Risk Management Plan is submitted by the Kimberly-Clark Tissue Company, Everett, Washington to comply with Section 112(r) of the Clean Air Act Amendments of 1990. This Executive Summary is provided to review and explain the plan elements, and to demonstrate Kimberly-Clark's continuing commitment to run an operation in Everett which is safe both to its employees and the surrounding community. Facility Description and Regulated Substances The Kimberly-Clark (K-C) Everett mill consists of a 500 air dried metric ton ammonium based sulfite pulp mill, a bleach plant, two pulp drying machines, and five paper machines. The pulp mill was built in the 1930s and was owned by the Soundview Pulp Company until the early 1950s, when it was purchased by Scott Paper Company. Scott Paper added paper machines and owned the operation until it merged with Kimb erly-Clark Corporation in 1995. In the sulfite pulping operation, softwood and hardwood chips are cooked in batch digesters utilizing ammonium bisulfite cooking acid prepared on site. The cooking separates the pulp fibers from the binding material (lignin) which holds them together. To prepare the cooking acid, sulfur dioxide gas (SO2) is mixed with an aqueous solution of ammonia (NH3). The sulfur dioxide is primarily generated by burning elemental sulfur, but is also reclaimed from the recovery boiler flue gas. Alternatively, it is obtained by the purchase of pressurized SO2 gas. This purchased "liquid SO2" is brought in by truck and stored in two 100-ton tanks located inside the pulp digester building. This quantity of SO2 is above the 5000 pound threshold for the Risk Management Program; consequently, it is subject to the RMP regulations. The ammonia is brought to the site in anhydrous form via 80 ton rail cars. This quantity exceeds the 10,000 pound RMP threshold for anhydrous ammonia; consequently, it is subject to the RMP regulations. The ammonia is pumped from the rail cars and diluted with water prior to storage in a 150,000 gallon tank. The aqueous ammonia is stored at approximately 20% strength; this quantity stored exceeds the 20,000 pound RMP threshold for aqueous ammonia, so aqueous ammonia is also subject to the RMP regulations. The ammonia solution is employed on site not only to prepare the cooking acid, but also for pollution control: it is used as a reactant in the sulfite recovery boiler to remove nitrogen oxides from air emissions, and it is used in the mill's secondary wastewater treatment plant to provide the nutrients needed for proper operation. It is also used to buffer concentrated spent sulfite liquor prior to storage. Pulp leaving the digesters is transported to three counter-current pressure washers; weak spent sulfite liquor from the washers is transported to multiple effect evaporators where it is con centrated. The concentrated sulfite liquor is then burned in the sulfite recovery boiler to generate steam. After washing, the sulfite pulp is bleached. The bleach plant currently utilizes three bleaching stages: chlorination, caustic extraction with oxygen, and hypochlorite. Chlorine, used directly in the chlorination stage and indirectly for the manufacture of sodium hypochlorite bleach liquor, is purchased directly and stored on site. The chlorine is imported to the mill by rail car and is presently forced out of the car to a storage tank utilizing a nitrogen pressure pad. A pressure pad is also used to push the chlorine from the tank to the bleaching process. After approximately September 1, the tank will be abandoned and the chlorine will be forced to the process directly, again using nitrogen as the driver. The total quantity of chlorine connected at one time is 90 tons. As the threshold quantity for chlorine is 2,500 pounds, chlorine is a covered RMP chemical . Under the terms of the EPA Cluster Rule, the mill is converting to an elemental chlorine free (ECF) bleaching process, which will be in operation by April 15, 2001. The revised process will also consist of three stages: chlorine dioxide, caustic extraction with oxygen and peroxide, and chlorine dioxide. A new chlorine dioxide generator will be constructed on site; elemental chlorine will no longer be used. A revised Risk Management Plan will be submitted to EPA prior to the startup of the new bleaching system. Kimberly-Clark's Safety Program We at Kimberly-Clark view safety as the most important aspect of our operations. Consequently, not only what we do, but also how we do it is of utmost importance to us at Kimberly-Clark; this world-class safety philosophy extends to all facets of our operations. The mill's chemical safety record speaks for itself: over the past five years, there have been no deaths, injuries, or significant property damage on site, or known of f site deaths, injuries, evacuations, sheltering in place, or environmental damage caused by accidental releases from RMP covered processes. The facility employs a full time Safety Manager and three environmental professionals. An environmental engineer monitors the Process Safety and Risk Management programs, ensuring the elements of these programs as listed below are properly executed. In addition, the mill maintains an emergency response (HazMat) team staffed with trained individuals; this team is available 24 hours a day. The HazMat team conducts quarterly drills to respond to simulated chemical accidents. A plant health and safety committee, composed of representatives from both the salaried and hourly work force, meets regularly to review all aspects of safety at the site. Finally, the company's insurance carrier, Factory Mutual, conducts annual audits which includes evaluation of the safety of process equipment. For equipment and operations associated wit h its chlorine, sulfur dioxide, and anhydrous ammonia systems, the Kimberly-Clark Everett Mill is subject to OSHA's Process Safety Management (PSM) regulations and to the analogous program codified in EPA's RMP requirements. While not covered by PSM, the aqueous ammonia system is also covered by the EPA program. Both rules require the following stringent activities which are practiced at the Everett site to minimize the potential for an accidental release: Review of the design of all equipment and controls to ensure proper lay out and installation. Updating of standard operating procedures to include specific information on safety procedures. All procedures must be reviewed and certified annually. Initial safety training and 3-year refresher training for all operators and maintenance staff. Procedures to ensure that all contractors receive the same safety training that Kimberly-Clark provides for its own employees. Regular inspection of all equipment, monitoring sys tems and controls, with stringent documentation of all inspections. Prompt corrective action for any non-conforming items identified by the regular inspections. Rigorous safety reviews conducted prior to system startup if any equipment or operations are modified. Stringent investigation of releases of any size and any "near-miss" incidents that might have led to a release. Periodic evaluation of the safety records of all outside contractors who work on the regulated systems. Development of an effective emergency response program. Implementation of an employee participation plan to ensure that all plant-wide staff are aware of these programs, and are actively consulted regarding safety issues. Independent audits of the entire PSM program and RMP program every three years. Safety is provided not only by the above procedures, but also by actual hardware installed on each chemical system: The liquid sulfur dioxide system is equipped with automatic shutoffs in case of an emergency. Any system overpressure would cause SO2 to vent back into the SO2 collection header. The header is vented back to the absorption tower, part of the acid making system. Any excess SO2 would react to form sulfite cooking acid. The anhydrous ammonia system is equipped with pressure relief valves, automatic shutoff devices, temperature regulators, video monitoring, and leak detection devices. Any overpressure would normally vent to the aqueous ammonia tank. The aqueous ammonia system is equipped with emergency shutoffs, pressure control, and leak detection devices. Overpressure normally vents from the tank via a stack equipped with a scrubber which converts any gas back into ammonia solution. The chlorine system also has automatic shutoffs. On-line pressure regulators normally handle overpressure with expansion chambers, although severe overpressure would cause venting to a suppression tank where any leak would be neutralized. This system also ha s leak detection devices, and is being equipped with video monitors. Emergency Response Procedures Kimberly-Clark uses its Emergency Response Guidebook to provide step-by-step procedures for emergency response in the unlikely event of an accidental release. The key elements of the emergency preparedness program are as follows: All plant staff are trained in the specific elements of the program. A team of engineers, supervisors and operators are trained, certified and equipped for hazardous materials (HazMat) emergency operations to stop uncontrolled releases. The plant uses a combination of audible alarms and a plant loudspeaker system to alert the staff of a potential accident and to conduct in-plant communications. In the event of a large release the facility would immediately contact a telephone call list that includes the Everett Fire Department (911) and the Snohomish County Local Emergency Planning Committee (LEPC). K-C is providing the county "911" system with an Emergency Alert System (EAS) whereby citizens can be advised of a problem and given directions via "Emergency Broadcast System" interruption of radio and television transmissions. Steps To Improve Safety Based on recent safety reviews that were conducted as part of the evaluations for EPA's Accidental Release Prevention Program, Kimberly-Clark has implemented the following actions to either reduce the likelihood or severity of potential chemical releases: Reduced Storage of Chlorine Kimberly-Clark recently stopped importing elemental chlorine to the mill via barge, and replaced the barge facility with a rail car unloading system. This modification greatly reduced the amount of chlorine stored at the mill. Previously the mill stored anhydrous chlorine at the facility in a 720 ton shore tank. From June until September of this year, 55 ton rail cars will unload directly to this existing tank. The quantity stored in the tank has been admini stratively limited to a maximum of 90 tons. When the tank level drops below 35 tons, filling from a 55 ton rail car can commence. Operators will check and record tank levels utilizing the tank level gauge, to insure that unloading does not commence until less than 35 tons is in the tank. After September of this year, a new rail car unloading station will be in place and the chlorine shore tank will be demolished. Chlorine will be forced directly to the bleach plant from rail cars. At this point the mill will begin utilizing 90 ton rail cars, reducing the number of trips and unloading events required. Future Discontinuation of Elemental Chlorine Usage Kimberly-Clark is completing engineering design for a new bleach plant that will use aqueous chlorine dioxide instead of elemental chlorine. After the new bleach plant is completed in the year 2000 the mill will no longer use elemental chlorine. This will provide less transportation risk as chlorine rail cars will no longer be required. The chlorine dioxide solution will be made on site from chemicals which pose no community hazard and will essentially be used as it is made; only 130,000 gallons will be stored. Tanks for the new chemicals will be located on the site of the former chlorine tank. The new chlorine dioxide tank will be surrounded by a concrete dike with sufficient capacity to fully contain a complete tank breach. The downwind impacts of a hypothetical release of aqueous chlorine dioxide solution will be much less significant than a hypothetical chlorine release. This Risk Management Plan will be updated next year prior to the startup of the chlorine dioxide system. Improved Traffic Barriers Kimberly-Clark evaluated potential traffic accidents that could damage piping containing aqueous ammonia solution, and installed new traffic barriers at some locations. After installation of the barriers, there is no realistic likelihood of a traffic accident causing damage t o process piping at the ammonia system. Enclosure of Liquid Sulfur Dioxide Tanks The two liquid SO2 tanks are located in the west end of the pulp digester building. Historically this end of the building was open to the atmosphere. Doors have been refurbished to enclose these tanks, which reduces significantly the distance any release would travel. Community Cooperation Based on the history of the plant, a significant accidental release is only a remote possibility. However, since such a release could impact industries, commercial areas, and residential areas, Kimberly-Clark is working with the Snohomish County Local Emergency Planning Committee to minimize any potential impact. K-C hosted the initial meeting of a LEPC committee devoted to Risk Management Planning, and hosted the quarterly meeting of the entire LEPC on June 15, 1999 to describe the mill's RMP plan and allow emergency responders an opportunity to tour the site. Company personnel have also beco me actively involved on the LEPC Board, and have assisted the LEPC in preparation of a brochure which describes what to do in case of an emergency. Presently in the County, the Department of Emergency Management (DEM) operates an Emergency Alert System (EAS) during normal business hours. If a natural disaster or chemical release occurs during these hours (Monday - Friday, 9 - 5) responders can activate the "Emergency Broadcast System" and send an alert to local television and radio receivers. Thus if a major release occurred at Kimberly-Clark during these hours, the K-C procedure of calling Snohomish County DEM would be sufficient to inform the community of a problem. However, as K-C is a 24-hour operation this system was not deemed adequate for response to potential upset conditions. Consequently, K-C is purchasing an EAS for the County "911" service which operates 24-hours a day, 7 days a week. This should greatly reduce community risk should a major chemical rel ease or other catastrophe occur. Hypothetical Accidental Release Scenarios The Risk Management Plan must assess the downwind impacts of hypothetical uncontrolled accidental releases. EPA requires facilities to model the distance that a plume of released gas would travel before it dispersed to an ambient concentration equal to the "Toxic Endpoint Concentration." The Toxic Endpoint Concentrations for various compounds are specified by EPA, and are generally concentrations that would cause no lasting physical harm but could interfere with the ability of people to leave the area. The Toxic Endpoint Concentrations for the RMP chemicals at the facility are: 200 parts per million (ppm) of ammonia; 3 ppm of chlorine; and 3 ppm of sulfur dioxide. Kimberly-Clark conducted safety reviews with plant operators, engineers, and safety managers to evaluate a wide range of hypothetical accidents that could cause releases of ammonia, chlorine or sulfur dioxide. In accorda nce with EPA's rule, two general types of hypothetical accidental release scenarios were developed: The "Administrative Worst-Case Release" that arbitrarily assumes the entire contents of the largest container of chemical is released to the atmosphere in 10 minutes. Kimberly-Clark is unaware of any conceivable event that could actually cause such a catastrophic release at the Everett mill. "Alternate Release Scenarios", which are releases that the safety review teams concluded have a realistic (but small) chance of actually occurring at the mill. These hypothetical releases generally consist of flange leaks, temporary process upsets, and breakage to pipes or tanks. 1. Worst-Case Release Scenario for Chlorine Anhydrous liquid chlorine (chlorine gas that is stored as a liquid under pressure at ambient temperature) is imported to the site by rail car and stored in a tank, the contents of which is limited to 90 tons. (As discussed previously, after ca. September 1, 1999, the tank will no longer be used, and chlorine will be drawn directly from 90 ton rail cars). The Administrative Worst-Case Release Scenario assumes that the entire 90 tons of chlorine in the tank or in a car are emitted as a gas cloud in 10 minutes, during a period of exceptionally calm winds and stagnant atmospheric conditions (1.5 meter/second wind speed and "F stability") that would result in minimal dispersion of the gas cloud as it blew downwind. At a recent technical conference, a speaker from a southern mill put the worst case release scenario into perspective. He calculated that a discharge of the entire contents of a 90 ton chlorine rail car in 10 minutes would require blasting a 3 foot diameter hole into the car. Since the car is stationary when on the plant site, it is difficult to conceive what sort of force short of an asteroid collision could cause such a cavity. EPA's scenario contemplating full evaporation in 10 minutes is equally extraordinary. T he thermodynamic properties of anhydrous chlorine indicate that such a large instantaneous gas release is not possible. If the 90 tons of liquid chlorine was somehow discharged from the tank or car it would spill onto the ground and immediately cool itself until it formed a puddle of ice, which would take much longer than 10 minutes to evaporate into a gas cloud. To evaporate the chlorine in 10 minutes would require a heat source equivalent to a small boiler, but no such heat source is present in the vicinity of the chlorine storage area. Finally, this imaginary heat source would create convection currents, increasing the height of the plume. But EPA's modeling directive assumes the gas cloud remains at ground level. Thus the worst case release scenario violates the laws of physics and provides little useful information. Nevertheless, the RMP rule dictates that the Worst-Case Scenario assumes the release of 90 tons of gaseous chlorine, so Kimberly-Clark used the mos t recent "RMP*Comp" computer model to estimate the downwind impacts for the 90 ton chlorine release. The model was set to use "Urban" surface roughness conditions to account for urban areas, rolling terrain, and coniferous forest in the Everett vicinity. RMP*Comp indicates that the gas cloud would travel 14 miles before it dispersed to the 3 ppm Toxic Endpoint Concentration. 2. Alternate Release Scenario for Chlorine Kimberly-Clark's safety review team selected the following hypothetical accident as the Alternate Release Scenario: a large earthquake breaks a 65-foot long pipe connecting the tank to the bleach plant (the scenario will be similar after the tank is removed and the process is run from directly from rail cars). The scenario assumes that liquid chlorine flows from the broken pipe for 2 minutes before the bleach plant operator activates remote emergency shutoffs, after which time the chlorine drains by gravity onto the ground. A total of 28 gallons (363 p ounds) of liquid chlorine would spill onto the ground, form a pool, immediately cool to its boiling point temperature (-29 degrees F), and form a puddle of solid chlorine "ice". It is estimated that 60 percent of the solid puddle (220 pounds) would evaporate in 20 minutes to form a gas cloud that could blow downwind. The 20- minute release period used for this calculation corresponds to the averaging time for the ERPG-2 concentration that EPA used as the basis for the Toxic Endpoint. Kimberly-Clark reviewed historical wind speed and direction patterns from a weather station operated near the mill by the Puget Sound Air Pollution Control Agency (PSAPCA). The station showed that the prevailing wind direction is toward the west (blowing from the mill away from populated areas), and the median wind speed is 1.8 meters/second. Although EPA suggests that facilities may use a relatively high wind speed of 3.0 meters/second for modeling the Alternate Release Scenario, Kimberly- Clark elected to use a reduced wind speed even though it results in downwind impacts that are more severe than if EPA's suggested wind speed was used. To account for the measured low wind speeds, Kimberly-Clark modeled the downwind impacts by averaging two values taken from EPA's "RMP-COMP" model: the value for the Worst-Case Release (1.5 meters/second wind speed and F stability), and the value for the Alternate Release (3.0 meters/second and D stability). As shown in Figure 1 the Alternate Release Scenario chlorine plume was modeled to travel 1,100 feet before it dispersed to the 3 ppm Toxic Endpoint Concentration. The prevailing wind direction at the Everett mill is toward the west, which would normally blow the hypothetical release out into Everett Harbor. However, it is possible that the wind could blow the plume toward populated areas. As shown in Figure 1 such an event could affect some residential areas, commercial areas, and industrial facilities adjacent to the mill. Therefore, as described in the section entitled "Emergency Response Program," Kimberly-Clark is working with the LEPC to facilitate prompt notification of those nearby facilities in the unlikely event of an actual release. 3. Alternate Release Scenario for Sulfur Dioxide Kimberly-Clark's safety review team selected the following hypothetical accident as the Alternate Release Scenario: a large earthquake breaks a 420-foot long pipe connecting the SO2 storage tanks to the processing plant. The entire contents of the pipe (590 pounds of anhydrous liquid) spills onto the ground, forms a liquid pool that immediately cools to its boiling point temperature (-14 degrees F), and forms a puddle of SO2 "ice". It is estimated that 60 percent of the solid puddle would evaporate in 20 minutes to form a gas cloud that could blow downwind. The resulting gaseous SO2 release is 17.5 pounds per minute for the first 20 minutes. After that time the remaining SO2 would volatilize slo wly. Of the 590 pounds of spilled liquid, only 350 pounds would be released as a gas in the first 20 minutes. The 20-minute release period used for this calculation corresponds to the averaging time for the ERPG-2 concentration that EPA used as the basis for the Toxic Endpoint. As described previously, PSAPCA's nearby weather station indicates that the historical median wind speed at the mill is 1.8 meters/second. To account for that low wind speed, the downwind SO2 impact caused by the hypothetical 17.5 lbs/minute release was calculated by averaging two values from EPA's RMP*Comp dispersion model: the value for the Worst-Case Release (1.5 meters/second wind speed and F stability), and the value for the Alternate Release (3.0 meters/second and D stability). As shown in Figure 1 the Alternate Release Scenario sulfur dioxide plume was modeled to travel 1,300 feet before it dispersed to the 3 ppm Toxic Endpoint Concentration. The prevailing wind direction at the Everett mill is toward the west, which would normally blow the hypothetical release out into Everett Harbor. However, it is possible that the wind could blow the plume toward populated areas. As shown in Figure 1 such an event could affect some residential areas, commercial areas and industrial facilities adjacent to the mill. Therefore, as described in the section entitled "Emergency Response Program," Kimberly-Clark is working with the LEPC to facilitate prompt notification of those nearby facilities in the unlikely event of an actual release. 4. Alternate Release Scenario for Anhydrous Ammonia Kimberly-Clark's safety review team evaluated a wide range of hypothetical events, and selected the following scenario to represent releases of anhydrous ammonia. Anhydrous ammonia is imported to the facility in rail cars. A gasket on the unloading rack between the rail car and Kimberly-Clark's process line develops a leak. The leaking gasket is exposed to liquid ammonia at a pres sure of 120 psig, which results in a release of ammonia droplets. An ammonia monitor at the unloading station would detect the leak and automatically alert the control room, which would dispatch the mill's HazMat team to the unloading area to repair the leak. The TANKLEAK emission module of the AIRTOX model was used to calculate the ammonia emission rate. Based on an assumed 1/8-inch hole size and a system pressure of 120 psig the calculated release rate is 2.5 gallons per minute (13 pounds per minute). As described previously, PSAPCA's nearby weather station indicates that the historical median wind speed at the mill is 1.8 meters/second. To account for that low wind speed, the downwind ammonia impact caused by the hypothetical 13 lbs/minute release was calculated by averaging two values from EPA's "RMP*Comp" dispersion model: the value for the Worst-Case Release (1.5 meters/second wind speed and F stability), and the value for the Alternate Release (3.0 meters/second and D stability). As shown in Figure 1 the Alternate Release Scenario ammonia plume was modeled to travel 800 feet before it dispersed to the 200 ppm Toxic Endpoint Concentration. The prevailing wind direction at the Everett mill is toward the west, which would normally blow the hypothetical release out into Everett Harbor. However, it is possible that the wind could blow the plume toward populated areas. As shown in Figure 1 such an event could affect some residential areas, commercial areas and industrial facilities adjacent to the mill. Therefore, as described in the section entitled "Emergency Response Program," Kimberly-Clark is working with the LEPC to facilitate prompt notification of those nearby facilities in the unlikely event of an actual release. 5. Alternate Release Scenario for Aqueous Ammonia Solution As described previously, aqueous ammonia is manufactured onsite by blending anhydrous ammonia with water to a solution strength of 20%, cooling the soluti on in a heat exchanger, and storing the solution in a large storage tank. Kimberly-Clark's safety review team evaluated a wide range of hypothetical release events, and selected the following event to represent releases of aqueous ammonia. A gasket on the heat exchanger processing 20% ammonia solution develops a small leak (assumed to be 1/8 inch diameter). Equations from EPA's "RMP Offsite Consequence Analysis Guidance" were used to estimate the leakage flow rate. At the 25-30 psig working pressure, the 1/8-inch gasket leak would cause a leakage flow rate of 2 gallons per minute (4 pounds per minute) of ammonia. As a conservative step it was assumed that all of the ammonia in the spilled solution would volatilize immediately to form a gas cloud. Ammonia detectors in the area would detect the leak and alert the control room, which would shut off the feed pumps to the system and stop the leak. The total duration of the leak would be less than 15 minutes, after which th e ammonia emissions would be limited to relatively small amounts of evaporation from the accumulated pool of spilled solution. EPA's "RMP*Comp" dispersion model was used to estimate the downwind impacts. Based on "Urban" surface roughness to account for tall buildings near the release site the "RMP*Comp" model predicts that the ammonia cloud would travel less than 500 feet before dispersing to the 200 ppm toxic endpoint concentration. The modeled distance to the toxic endpoint concentration is less than the distance to the facility boundary. |