Inspection Detail

Inspection: 106702293 - Memc Electronics Materials

Inspection Information - Office: Saint Louis Area Office

Investigation Summary

DURING THE NORMAL ETCHING PROCESS OF SILICON WAFERS THE EXHAUST FAN USED TO VENTILATE AN ENCLOSED HOOD STOPPED WORKING. THE HOOD ENCLOSED AN AUTOMATED PROCESS WHERE SILICON DISCS ARE FIRST DIPPED INTO A SOLUTION OF KOH AT 45% AND ABOUT 90 DEGREES C, AND THEN TRANSFERRED TO A 0.5% HCL SOLUTION AT ROOM TEMPERATURE. IT WAS DETERMINED THAT BECAUSE THE BUILDING INTERIOR WAS UNDER NEGATIVE PRESSURE, AND ALSO BECAUSE OF PREVAILING ATMOSPHERIC CONDITIONS, THE EXHAUST DUCT CONTENTS WAS FORCED BACK INTO THE WORK AREA. FIVE EMPLOYEES WERE EXPOSED TO THE KOH VAPOR/MIST. THEY WERE HOSPITALIZED OVERNIGHT AND WERE TREATED WITH OXYGEN. THEY WERE DIAGNOSED WITH UPPER RESPIRATORY IRRITATION AND LUNG CONGESTION. THE FIVE EMPLOYEES ALL RETURNED TO WORK THE FOLLOWING WEEK. AS A RESULT OF THE INCIDENT AN ALARM HAS BEEN PLACED ON THE HOOD, ALTHOUGH NO SUCH ALARM IS REQUIRED BY OSHA. A BACK-UP EXHAUST IS ALSO BEING CONSIDERED.

Keywords: RESPIRATORY, LUNG, VENTILATION, INHALATION, CHEMICAL VAPOR, TOXIC FUMES