Transuranic Waste Operations

The Defense Nuclear Facilities Safety Board (DNFSB) publishes a weekly site report about LANL (and other sites) which is available on their website. These one page reports are released sporadically and are often over a month old before I get to read them. They usually contain something I would have covered on the blog if I had more timely access to them. For example, the report for the week ending November 28, 2008 was recently released. Here's a portion of what it says:

Transuranic Waste Operations: Last Sunday, a deflagration occurred during remote drum venting operations at Area G. The affected drum contained roughly two Pu-239-equivalent curies of material that was cemented into 35 one gallon containers and packed in a 55 gallon drum in the 1980's. The deflagration did not cause energetic ejection of drum contents and the venting enclosure was not breached so all resultant contamination was contained in the enclosure. Five operators involved in the evolution were taken to the hospital after reporting respiratory distress thought to be caused by chemical vapors emanating from the newly vented drum or combustion products from the deflagration. All operators have reported back to work, although one remains on medical restriction.

The cause of the deflagration remains unclear and investigation continues. Eight operators were maintaining the TSR-controlled 90 foot separation distance from the HEPA-filtered enclosure when the event occurred. Personnel reported hearing an abnormally loud noise when the spark-resistant venting tool punctured the 55 gallon drum and almost immediately thereafter smelled an unusual sulfurous odor. Three operators outfitted in personnel protective equipment and respirators (the balance of operators were in street clothes) made a re-entry into the enclosure, observed evidence of a deflagration, and exited the area. Soon after, the five operators developed respiratory symptoms.

The LANL Emergency Management and Emergency Response groups and the Los Alamos Fire Department were notified and responded to the event. Laboratory HAZMAT personnel characterized the drum using thermography to detect any residual combustion. When none was observed, they re-entered the enclosure and plugged vent holes with sample ports, thereby resealing the 55 gallon drum. While the Fire Department did transport the five affected operators to the hospital, they never entered Area G to survey the scene of the deflagration. The affected drum has since been decontaminated, re-secured in a filtered 85 gallon overpack and restored to a segregated and tightly controlled unvented drum storage array pending further investigation and the development of a path forward.

There were other worker exposures in 2008 that never made it into the news, but this is perhaps the worst. Does anyone know of a single incident that resulted in exposure to contamination of more than five people last year?