A new technical report that details the consequences of toxins in smoke plumes from spilled crude oil shows that the quantities of these combustion by-products vary greatly and have different levels of toxicity.
Prepared by Aristatek, Inc, a provider of hazardous materials planning and response solutions, said it prepared its technical paper,
Toxic Consequences of Smoke Plumes from Crude Oil Fires, in response to “several high-profile accidents in 2013 have highlighted the inherent dangers this substance can present, especially those effluents produced by burning crude oil.
The technical report analyzes these effluents and the company is making it available at no cost to all emergency response and public safety/health professionals at no cost to assist in their responsibility to protect their communities.
“We went back and forth” on the technical paper “as our analysis lead us in different directions,” Aristatek’s C. Scott Bunning told Homeland Security Today. “What we discovered during our analysis is that some toxic threats can extend beyond the recommended initial evacuation zone of the Department of Transportation’s Emergency Response Guidebook (ERG) of on-half mile in all directions.”
But the ERG made “no recommendations on downwind protective action distances for crude oil fires, so our data may be some of the first out there on this,” Bunning said.
“As crude oil burns, the resulting smoke contains chemicals which are harmful to humans if exposed to critical concentrations,” Aristatek said. “Formaldehyde, carbon monoxide, benzene, sulfur dioxide and particulates are the major effluents found in the smoke as reported in technical literature and are analyzed in the brief,” which “points out that in addition to the isolation and initial evacuation zones recommended by Guide 128 of the 2012 Emergency Response Guidebook from the Department of Transportation, emergency planners and responders may need to consider taking protective action downwind from a crude oil fire involving a railcar.”
“During a train derailment involving crude oil,” the company explained, “the immediate threats responders worry about the most often are the vapor cloud explosions and pool fires. But another threat are the toxins emitted in the smoke plume for folks that are downwind from the accident. We felt analyzing this threat could help emergency managers and responders make more informed decisions during planning, training and response for these types of accidents since there are no green pages associated with crude oil in the ERG.”
AristaTek’s analysis treats each substance individually by first calculating an expected total amount of each that would be given off for two different amounts of crude oil burned (30,000 and 10,000 gallons).
As an example of the brief’s methodology, formaldehyde can be produced at a level of 139 mg per kg of crude oil burned, while carbon monoxide can be produced at 30,000 mg per kg of crude oil burned. An average release rate is calculated based on the fire lasting an assumed 4 hours. Since each substance has a different toxicity level, the downwind protective action distance for each substance is calculated using the company’s PEAC-WMD hazardous materials technical reference and modeling software, using an assumed set of meteorological conditions to predict that substance’s potential consequence on individuals downwind. Some substances were found to have relatively small protective action distance (formaldehyde at 600 feet) and others have larger protective action distances beyond the half-mile recommended by the ERG (sulfur dioxide at 1.2 miles).
Also included in the technical paper are the signs and symptoms of exposure to these effluents for reference by responders.
Photo: Crude oil fireball and smoke plume during train derailment in Cass County, North Dakota, December 2013. Photography ©Dawn Faught 2014 -- All Rights Reserved
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