CSB releases report on MRR tank explosion

Lack of hazard identification contributed to fatal accident

THE US Chemical Safety Board (CSB) has found that a lack of hazard identification processes contributed to the tank explosions that killed three people at the Midland Resource Recovery (MRR) facility in West Virginia in 2017.

One of the services performed by MRR is the decommissioning of the tanks used to add the odourants known as mercaptans to natural gas. The MRR process added sodium hypochlorite to the odouriser vessels to remove the odour from the steel so that it could be scrapped. The vessels were sealed for a time, creating what MRR referred to as process water. On 24 May 2017, when the process water was being drained from a tank, an explosion occurred which killed two workers, one of whom was the founder and President of MRR. Another worker was seriously injured. A second explosion occurred on 20 June which killed a contractor who had been hired by MRR to perform investigation and mitigation work.

The CSB also found research which suggested that the methanol mixed with sodium hypochlorite can form methyl hypochlorite, a highly explosive chemical