The US Chemical Safety Board (CSB) has publically expressed dismay and disappointment in a letter to Tesoro Corporation in San Antonio, TX. It is in regard the apparent unwillingness of the company to allow CSB investigators to come on site and continue with the investigation of an industrial accident or, if you prefer, incident. Apparently two workers were splashed with sulfuric acid and had to be choppered out for treatment.
From what I gather from the CSB letter, Tesoro doesn’t believe that the incident rises to the level of seriousness to justify a CSB investigation. That is my own interpretation.
At first blush it would seem that Tesoro has a point. While it is something that OSHA would cover, does it really necessitate attention by the CSB? By itself it seems questionable. But when you consider that Tesoro had an 7-fatality explosion and fire at its Anacortes refinery in April of 2010, perhaps the scrutiny seems less unreasonable.
The refinery explosion was determined to result from high temperature hydrogen attack within a 40 year old shell and tube heat exchanger. Catastrophic structural failure on startup after a scheduled tube cleaning resulted in an explosion and fire with immediate and delayed fatalities.
It seems to me that the failure of a high temperature heat exchanger after 40 years of service handling hydrogen and naphtha has more to do management policy on equipment service life than anything else. This speaks to prudent administrative and engineering controls on plant safety. A shell and tube heat exchanger has no moving parts to fail. It just sits motionless doing it’s function. There are no failing parts to replace other than leaky tubes and valves. Perhaps no one considered that the inherent nature of the gas and thermal cycling was deleterious to the integrity of the metal shell? Perhaps there was no enthusiasm to define official hours of operating life. Plant managers are always under pressure to minimize operating costs. This is especially true of plants producing high volume low margin commodities.
But here is the rub. Everything has a failure rate. This is especially critical for equipment under high temperature and pressure. The first layer of administrative control is for management to make allowances for materials in extreme environments. Anacortes is not the only recent incident where component failure has occurred in equipment performing under demanding conditions. Before the engineers can make equipment specifications for this, management has to conform to the notion that some parts of a plant should have better definition on service life. They should demand it of their design people and support engineering when the time comes to replace a component.
If the CSB believes that a company has weak administrative controls that influence plant safety, then I think they should investigate.