On August 6th, Ecology responded to a large fire in Tacoma involving a major stormdrain line in a ravine called the T-Street Gulch. When Ecology arrived on scene, the City of Tacoma FD was fighting a major fire with flames reported to be exceeding 40 feet in height. (EPA was not notified of this incident until 11 August 08)
Throughout the past week (since the fire) workers from the City of Tacoma along with Ecology spill responders were unable to access the damaged pipe in the bottom of the Ravine due to noxious vapors and readings of explosive vapors. Ecology suspected that flammable solvents had been dumped into the storm drain and were to blame for the original fire and resulting persistent vapors. While responders attempted to access the stormdrain from manholes upstream of the fire location, efforts were not successful in determining if there was still any material remaining in the line.
Ecology/City of Tacoma requested EPA Emergency Response assistance with more sophisticated air sampling and monitoring as well as site entry personnel equipped with proper respiratory and personnel protective equipment.
OSC Dave Rees along with START Team members responded to Ecology's request and mobilized to the Tacoma site on 11 August 08, arriving on scene @ 1300. After taking air readings at the site and within the stormdrain it was determined that the vapors and explosive readings found last week had dissipated and that with the exception of slightly elevated reading for formaldehyde, (approx half of the TWA) no additional contaminants were found. A more thorough assessment revealed that the fire had apparently been set or started from the outside of the stormdrain pipeline rather than from a material inside the pipe. The stormdrain is constructed of a 1 inch thick PVC-type walled pipe and it is believed that the persistent vapors may have been caused by the pipeline material smoldering. Once the material is ignited, the plactic burns like a tire fire.
