"707 bulkhead door that divides the construction split from the disposal split requires
manual operation and cannot be remotely shut, which is necessary for shifting to
filtration mode. During the initial entries after the event, underground services shut the 707 bulkhead door and regulator the afternoon of February 14, 2014. This
allowed the ventilation system to be placed in filtration mode. After the radiological
event the evening of February 14, 2014, it would not have been possible to place the
ventilation in filtration mode if 707 bulkhead door had remained open."
It is important to note that the WIPP facility has been trying to eliminate EPA requirements that they check for explosive gases. WIPPs desire to abandon such costly testing was based on an analysis claiming it was not possible for gas to build to explosive levels. Of course, that analysis would have been based on the on the assumption that the ventilation system was operating within design specifications. It is important to note that the location of the initial radiation alarm was precisely at the location where the analysis indicated explosive gases were most likely to concentrate.
Obviously after the fire, the ventilation system was no longer within design specifications, and the chance of explosion from combustible gases greatly increased. And more importantly for the risk of additional explosions and radioactive releases, the 2/14/14 explosion has resulted in the mine ventilation being massively out of spec. We believe the risk of additional explosive releases of radioactive materials at the WIPP facility is very high.