PVS Chemicals, Inc. (New York) - Executive Summary

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PVS Chemicals, Inc. (New York), located at 55 Lee Street in Buffalo, New York, is a manufacturer of all grades of sulfuric acid and fuming sulfuric acid (oleum).  In addition to sulfuric acid, PVS manufactures ammonium thiosulfate solution, sodium bisulfite solution and diethanolamine sulfur dioxide adduct.  Also, PVS maintains a storage and handling system for distribution of 31.4% to 35.2% hydrochloric acid. 
The products manufactured by PVS are basic in nature and are used in a wide variety of applications, including:  steel manufacturing, oil refining, photographic processing & development, water & wastewater treatment, agriculture fertilizer, soap & detergent processing, silicon wafer fabrication, pharmaceuticals and many others. 
The provisions of Section 112(r) of the Clean Air Act of 1990 (RMP) are applicable to PVS due to the on-site presence of certain chemicals included in Table 1 of Section 68.130 - List of Regulated Toxic Substances and Threshold Quantities for Accidental  
Release Prevention.  Specifically, anhydrous ammonia and anhydrous sulfur dioxide can be present on site as raw materials for the manufacture of ammonium thiosulfate solution.  Oleum (25% and 65% sulfur trioxide by weight) is present on site as a finished product.  Each of these substances can be present on site in amounts greater than the threshold quantities stated in Table 1 referenced above. 
In concert with an overall commitment to Responsible Care, it is the PVS policy to design, operate and maintain the manufacturing facility in such a manner that minimizes any risks to our employees, the local community and the environment.  In brief, our goal is as follows:  "No accidents, injuries or environmental mishaps". 
The PVS accidental release prevention policy encompasses the elements identified in OSHA's Process Safety Management program.  These elements include Hazard & Operability Studies (HazOps), routine mechanical inspections, management of change procedures and emergency plann 
ing, all with participation from hourly employees.  HazOps, which review process safety information, operating procedures and emergency actions, have been performed on all covered processes and many non-covered processes to identify scenarios with possible off-site consequences and to establish a corrective action plans.  Operator training is the backbone of the PVS accidental release prevention program with additional emphasis on safe mechanical design and simple yet sound operating procedures.  PVS endeavors to minimize risk while a process is still in the design phase of a project.  This is done by minimizing raw material inventory or by consuming raw materials directly from the shipping container, thus eliminating transfer risks.  All applicable federal, state and local rules and regulations are adhered to. 
Emergency planning at PVS includes a written Facility Response Plan that addresses activities at the facility, emergency procedures, evacuation plans and notification requireme 
nts.  This plan is shared with the Local Emergency Planning Coordinator, the local fire department, the New York Department of Environmental Conservation and the immediate community surrounding PVS.  For emergency community notifications, PVS can utilize an automated telephone system (CAN) to alert each household in the surrounding neighborhood.  For on-site activities, PVS employees are trained in OSHA HAZWOPER techniques. 
The RMP rule requires a Five Year Accident History.  Although the ammonium thiosulfate process did have a release of sulfur dioxide in excess of the reportable quantity in 1996, analysis of this incident and other incidents that have occurred over the past five years shows that no reportable accidents as defined in the RMP rule have occurred.  Note, the 1996 sulfur dioxide incident did not involve the use of anhydrous sulfur dioxide and did not cause any on-site or off-site injuries, property damage, evacuations, sheltering in place or environmental damage. 
As par 
t of the Risk Management Program Rule, PVS has performed off-site consequence analyses which include consideration of release scenarios involving a DOT approved tank trailer filled with anhydrous sulfur dioxide, a DOT approved railroad tank car filled with anhydrous ammonia, a storage tank filled with 25% oleum and a storage tank filled with 65% oleum.  In the scenario described as the "worst case release scenario", EPA states that "the owner or operator shall assume that the  maximum quantity in the largest vessel  is released as a gas over 10 minutes".  Additional scenarios, described as "alternative release scenarios" which are more likely to occur than the worst case, were also analyzed. 
Note, no consequence analysis for flammables was performed because no flammables listed in Table 3 for Section 68.130 - List of Regulated Flammable Substances and Threshold Quantities for Accident Release Prevention are present at PVS. 
In the "worst case release scenario",  the theoretical rele 
ase generating the greatest distance to an endpoint is if the entire contents of a 42,000 pound tank trailer filled with anhydrous sulfur dioxide (CAS 7446-09-5, Toxic Endpoint 0.0078 mg/L) was released over a 10 minute period.  The anhydrous sulfur dioxide is maintained in a liquefied state while under pressure in the tank trailer and the location surrounding PVS is urban.  RMP*Comp was used to analyze the consequence of the above release.  This release would have off-site consequences. 
This  "worst case release scenario" of releasing the entire contents of a tank trailer filled with anhydrous sulfur dioxide is highly unlikely due to several mitigating factors, including: 
     Anhydrous sulfur dioxide is only brought on site a few times per year when necessary to continue manufacturing ammonium thiosulfate during shutdown periods.  In 1998, eleven tank trailers of anhydrous sulfur dioxide were purchased through the entire year and in the first half of 1999 no tank trailers of anhydr 
ous sulfur dioxide were purchased for onsite use. 
     Anhydrous sulfur dioxide is shipped to PVS in properly maintained DOT approved pressure vessels.  These vessels are designed with pressure relief systems, emergency shutoff valves, excess flow check valves, and inspected regularly. 
     When an anhydrous sulfur dioxide tank trailer is on site and connected to the process, an extra employee, trained in the proper unloading procedures and emergency response, is specifically assigned to monitor the unloading of the tank trailer.  This employee continuously observes the trailer throughout the unloading period and can perform emergency procedures to shutoff and secure the trailer as necessary. 
The alternative release scenario analysis, which EPA guidance describes as "more likely to occur than the worst case release scenario", was conducted on each of the three covered processes.  Although this analysis must consider events that are more likely to occur that the worst case scenario,  
there is still a very low likelihood that any of the events analyzed could take place at PVS given the design of the process and the mitigation systems in place. 
The alternative release scenarios are as follows: 
     The 1" hose supplying anhydrous ammonia to the ammonium thiosulfate process fails catastrophically and over 5 minutes releases 7500 pounds of ammonia.  Although this analysis is based on manually closing the ammonia valve by operating personnel, an active mitigation would involve the automatic tank car shutoff system. 
     The 2" hose supplying anhydrous sulfur dioxide to the ammonium thiosulfate process fails with a 1" diameter tear in the transfer hose.  Over 5 minutes, this tear releases 12,600 pounds of sulfur dioxide.  Mitigation involves full attendance of the tank trailer as it is being unloaded and the emergency safety devices (excess flow valve and remote emergency shutoff valve) designed into the tank trailer. This alternative release scenario is deemed furthe 
r unlikely given that PVS only receives anhydrous sulfur dioxide for the ammonium thiosulfate process two to three days each year. 
     A 3" stainless steel pipeline carrying 30% oleum from process to a storage tank catastrophically fails and over 4 minutes releases 30,500 pounds of 30% oleum.  This scenario would be mitigated by the sound piping design and installation used to carry the oleum and the simple fact that the inventory of the process would be exhausted after 4 minutes. 
     A gasket in the 3" pipeline used to circulate 65% oleum fails and over 15 minutes releases 1200 pounds of 65% oleum.  The pipeline and valves in this system can be automatically and remotely shutdown once the problem is discovered.  This alternative release scenario is deemed further unlikely given that PVS only processes and loads 65% oleum two to three days each year. 
All four of the above alternative release scenarios will have off-site consequences. 
PVS realizes that accidents can have off-site c 
onsequences and so designs and operates the facility in a way to minimize the possibility of mishaps.  While no immediate process changes are planned as a result of this most recent consequence analysis, our program of constant inspections, audits, training and employee suggestions provide frequent opportunities to improve the safety and reliability of our covered processes.
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