Text For Citation: 02 Item/Group: 001 Hazard: CHEMICAL

SECTION 5(a)(1) of the Occupational Safety and Health Act of 1970: The employer did not furnish employment and a place of employment which were free from recognized hazards that were causing or likely to cause death or serious physical harm to employees in that employees were exposed to: At the clean-up room, where employees were exposed to the hazard of exposure to toxic gas(es) resulting from the mixing of incompatible chemicals. Conditions which could result in the mixing of such incompatible substances were not controlled in that: (a)The floor below the grating in the cleanup room was heavily littered with silicon wafers, had been in this condition for more than a year prior to the incident and continued to be littered even after the event. Silicon wafers can react with concentrated acid to form the toxic gas nitrogen dioxide. (b)The demonstrated potential for leaks from the pump for the Probetronics Etching machine, located above the grating and floor where silicon wafers were allowed to accumulate, was not controlled. The pump was used to supply concentrated acids to the etching process. The potential for hazardous release of toxic gas through the mixing of these incompatible chemicals was demonstrated during an incident on or about April 7, 1995. At that time a visible brown cloud of nitrogen dioxide, which can cause pulmonary edema and permanent lung damage, rose above the grating into the work area. Exposed employees required medical treatment. Recognized and feasible means of abatement for this hazard include, but are not limited to, the following: (1)Develop and implement a housekeeping program with scheduling for wafer removal at sufficient intervals to prevent the accumulation of silicon material at the floor. (2)Install and operate a leak detection system for the pump set-up. (3)Install a leak containment and drainage system such that any leaks of acid are contained and diverted from wafer materials. Develop and implement an associated pump/containment maintenance program to prevent leaks from occurring.