An oil spill recently occurred on an offshore production platform when safety equipment failed to operate.
Pipeline pumps transferring oil from a free-water knockout vessel gas locked and ceased pumping.
This resulted in a high oil level in the free-water knockout. A high liquid level shut-in device on the vessel failed to operate and oil flowed through the gas outlet line to a low pressure gas scrubber. The low pressure gas scrubber discharged the oil to a relief gas scrubber where it passed through an emergency overflow line into a skim pile. A high liquid level shut-in device on the relief gas scrubber did not operate because it was located two feet above the liquid overflow level. The skim pile fluid level built up to the high liquid level shut-in device which failed to operate because of a damaged float.