WACKER SILTRONIC CORP. - Executive Summary

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Description of Facility and Regulated Substances Handled 
 
Wacker Siltronic Corporation's (WSC's) facility in Portland, Oregon, manufactures high purity silicon wafers, the basic raw material for the electronics industry.  The facility has one administration building, two main process buildings (Fab 1 and Fab 2) and several auxiliary support buildings, including water and waste water treatment facilities.  WSC operates 24 hours per day, 7 days per week, except during occasional shutdowns for preventative maintenance activities, equipment installations, etc. 
 
The manufacture of silicon wafers entails the use of chemicals and the generation of wastes, some of which may be listed as toxic or hazardous under U.S. Environmental Protection Agency (EPA) regulations.  Currently, WSC does not have more than a threshold quantity of a listed substance under Clean Air Act Section 112(r) in a process onsite.  However, WSC plans to receive and store a listed hydrofluoric acid (HF) solution in quantit 
ies greater than the threshold quantity of 1,000 pounds. 
 
WSC's plan to convert to the listed HF solution aligns with the Chemical Conservation Program started at WSC in 1985.  This change will reduce overall acid quantities used in manufacturing.  
 
Worst-Case Release Scenario and Alternative Release Scenario 
 
Worst-case and alternative release scenarios were defined in accordance with EPA's Risk Management Program (RMP) Offsite Consequence Analysis Guidance (RMP Guidance) and the RMP regulations in 40 CFR 68. 
 
The worst-case release scenario is defined as the catastrophic failure of a HF solution storage tank.  The entire contents of the tank are assumed to be released instantaneously into the containment dike, forming a pool.  The liquid HF solution pool would then begin to evaporate and disperse.  This scenario is believed to be highly unlikely due to the event necessary to cause such a tank failure and the presence of monitoring programs to detect such a release. 
 
Based on the wors 
t-case release scenario, the distance to the toxic endpoint as defined in the RMP Guidance is approximately 1,500 feet.  The area of impact under this scenario reaches offsite receptors in the industrial area of Northwest Portland.  The area of impact is not believed to reach any residences in the area, however, a portion of U.S. Highway 30 and the Willamette River are included.   
 
Alternative release scenarios were developed to better represent the magnitude of a conceivable, although still unlikely, release.  The alternative release scenario is a leak in a HF solution transfer hose during off-loading from a tanker truck.  HF solution would leak out of the hose and form a pool.  The liquid HF solution pool would then begin to evaporate and disperse. 
 
Based on the alternative release scenario, the distance to the toxic endpoint as defined in the RMP Guidance is approximately 40 feet.  The area of impact remains onsite. 
 
Accidental Release Prevention Program Steps 
 
Steps taken by WSC to 
prevent accidental releases from bulk HF solution storage systems include the following: 
 
7 compilation of Safety Information 
7 completion of a Hazard Review 
7 review of Operating Procedures 
7 training 
 
The effectiveness of WSC's accidental release and emergency prevention program relies on many inspection and preventative maintenance activities including: 
 
7 Equipment inspection by Facilities Maintenance personnel.  This is done to detect any equipment or operational problems before they result in an equipment shutdown or emergency situation. 
 
7 Preventative maintenance by Facilities Maintenance personnel.  This routine maintenance is done to keep equipment in peak operating condition and to avoid shutdowns and emergency situations. 
 
7 Drain inspections by Facilities Operations personnel.  The correct operation of the drain system is a critical part in preventing emergency situations and in properly disposing of waste materials recovered from a chemical spill. 
 
7 Operational inspecti 
ons by Facilities Operations personnel. 
 
Inspection programs often overlap which provide for several groups inspecting plant operations at different times of the day for added protection against unforeseen problems. 
 
Five-Year Accident History 
 
WSC has not had a reportable accident related to bulk HF solution storage in the last 5 years.  WSC's plan to use a higher concentration HF solution has triggered a thorough review of the storage systems.  Compatibility has been confirmed as appropriate and several enhancements to the systems have been completed.    
 
Emergency Response Program 
 
WSC's Emergency Preparedness, Prevention and Contingency Plan Procedure (Contingency Plan) is designed to prevent sudden or non-sudden release of hazardous materials or waste constituents into the air, soil or surface water, which could threaten human health or the environment.  The Contingency Plan is implemented immediately whenever there is, or is perceived to be, a fire, explosion, or spill, at the fa 
cility. 
 
The Contingency Plan describes the procedures for contacting and the responsibilities of persons qualified to act as Emergency Coordinators (ECs).  These coordinators are members of WSC's Emergency Response Team (ERT).  ERT personnel are trained in preventing an emergency incident from harming employees and the environment.  In preparation for their ERT duties, team members receive extensive classroom and "hands on" training.  In addition to initial training, annual refresher and supplemental training is required.  The Contingency Plan also describes arrangements agreed to by local police and fire departments, hospitals, and contractors to coordinate emergency services in the event they become necessary.
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