Okmetic, Inc. - Executive Summary
Okmetic, Inc. is a wholly owned subsidiary of Okmetic Ltd., an international manufacturer and supplier of high quality Cz-silicon wafers for the semiconductor industry. Okmetic Ltd. currently has about 450 employees and 1999 sales of approximately 50 million dollars. The Company is committed to providing the highest quality semiconductors to industry while maintaining the highest standards of safety for employees and the public. The system described in this submittal is for the distribution of Hydrogen Chloride (HCl), the chemical of concern, gas to vacuum chambers used to manufacture epitaxial silicon wafers. The maximum inventory of HCl on site is 22,200 pounds. The Company has designed a safe HCl system that includes numerous alarms, automatic shutdowns, and employee procedures designed to insure that the HCl is safely stored and used in the process. All system components are designed in accordance with the applicable guidelines and recommendations of the American Society of M |
echanical Engineers (ASME), The American National Standards Institute (ANSI), The Occupational Safety and Health Administration (OSHA), and other appropriate industry standards for compressed gases and semiconductor facilities. Okmetic, Inc. is committed to immediate response and full cooperation with the authorities in the event of any kind of emergency situation at the facility.
HCl is a highly corrosive gas that will quickly combine with water vapor in the air to form Hydrochloric Acid. The acid will quickly react and form less harmful chloride salts and water in the environment. The above reactions occur quickly in the environment thus the reactive effects of a release will end shortly (within minutes to a few hours) of the time when the release stops. The company has taken every reasonable precaution to insure that any release is small. The larger storage vessels for HCl are protected DOT approved shipping containers. They represent a very low risk of releasing gas. HCl
gas is withdrawn from the storage tanks through a series of regulators and automatic valves equipped with monitors, alarms, and automatic shutdowns that vent to gas scrubbers should there be any leaks. Additionally, HCl gas is only withdrawn from the storage tanks as it is used. This minimizes the amount of gas that would be released from using the system. The pressure of the gas in the distribution system is kept relatively low to reduce the potential for leaks in the distribution system. The distribution system is constructed using corrosion resistant Hastelloy steel, with welded connections where possible, valve enclosures vented through scrubbers, purge systems vented through scrubbers, alarms with automatic shutdowns, manual shutdowns, and employee training.
In the event of a catastrophic or worse case release (3,000 lbs in 10 minutes or release of one HCl tube on the tube trailer) the impact area (determined by using the EPA RMP*Comp software) would be inside a 3.4 mile ra
dius (36.3 sq miles) from the site. This would affect approximately 45,000 people and include 21 schools and 35 other public buildings and places. The alternative release (146 lbs/min for 30 minutes or a broken ? inch supply line) scenario impact area would be inside a 0.7 mile radius (1.5 sq miles) from the site. This would affect approximately 1,800 inhabitants and include one school (Boyd Elementary) and one other public building. The Company's emergency response to a release is to notify and use the Allen Fire Department to respond and notify the area using the fire department's emergency warning system.
Safety is a prime concern of Okmetic, Inc. There have been no accidents involving a release of HCl at the facility in the past 5 years. Safety improvement is an integral part of operations. Safety improvements are made when changes in the system require them or a safer method of accomplishing a job is identified. Regular employee safety meetings, design reviews, and the Pr
ocess Hazard Analysis sessions are used to identify and implement improved safety procedures.