On the day of the incident, a contract worker used steam to heat the contents of a railcar to facilitate its unloading into process equipment. After the railcar was unloaded, the worker needed to remove the steam and condensate hoses from the railcar . The contractor verified that the steam and condensate isolation valves were closed and that steam was no longer draining from the condensate drain valve. While removing the steam hose from under the railcar, the contractor was sprayed with steam and hot condensate. The contractor was transported and admitted to a hospital for treatment.

 

The company's investigation identified that the typical practice used at the facility to isolate and depressurize the steam hose was to close Valve A while having Valve B and Drain Valve 1 open to allow residual steam to flow out of the hose. However, Valve A was broken in the open position and could not be closed. Instead, the contract worker closed Valve B, left Drain Valve 1 closed, and opened Drain Valve 2 (visually obstructed in by the steam supply hose) to drain both the condensate hose and the steam hose. Because of how the heating coil was configured within the railcar, this configuration trapped condensate in the steam hose.
The company's investigation found that when workers first identified the broken valve (Valve A), they should have used stop work authority to prevent the unloading equipment from being used until the valve was repaired. The company’s investigation also concluded that its written operating procedure did not effectively describe the process of draining steam or hot condensate from the railcar. In addition, the procedure did not explain how to verify that there was no pressure on the steam or hot condensate hoses. No instruments (such as a pressure gauge) or other safeguards were available to warn workers that the steam hose contained a dangerous amount of condensate.
Probable Cause
Based on the company's investigation file, the CSB determined that the probable cause of the incident was disconnecting a hose from a railcar that contained steam and hot condensate. A broken isolation valve on the steam supply piping changed how the steam and condensate hoses were isolated and drained, contributing to the incident. The lack of instrumentation or other safeguards to warn employees that the loading hose held a dangerous amount of condensate contributed to the incident.

 Source:CSB.gov