Document 1zLL0n82EnEw020p3gVdKEZo

VISTA CHEMICAL CO., ABERDEEN PLANT VCM COMPRESSOR UPGRADE - PHA COMPLETION REPORT SEPTEMBER 2, 1992 IV. SUMMARY OF IDENTIFIED POTENTIAL HAZARDS 1. CAUSE: Failure or accidental closing of the VCM vapor valve (00HV103) from the sphere, the liquid VCM valve (00HV102) to the sphere, or the railcar isolation valve (00XV120). CONSEQUENCE: Cavitation or dead-heading of the VCM compressors. This could potentially damage the compressors and subsequently cause a VCM leak. RECOMMENDATIONS: Include the inputs for these valves in the compressor interlocking, such that the compressors are shut down when any of these valves are closed. RESOLUTION: The above recommendation has been implemented into the electrical design and operating procedures. RISK RATING: 4 VAB.0001107935