Officials launched an all-night mission Sunday night to determine whether a failing pressurized tank at a Garden Grove aerospace company was still at risk of exploding, after days of rising concern that the vessel could trigger a BLEVE explosion. The work was intended to confirm that the pressure inside the tank had been released and that the threat had been eliminated.
By Sunday evening, the tank had reached 100 degrees Fahrenheit, the highest reading on its gauge, officials said. That came after readings of 90 degrees on Saturday morning and 77 degrees on Friday, even though the goal had been to bring the tank down to 50 degrees. The tank was filled with a toxic chemical, and officials had warned it could pose either an explosion risk or a major spill.
TJ McGovern said firefighters overnight detected a potential crack in the tank, and he said that crack could be relieving some of the pressure. He also said the new information could change the response. “With this new information, it could change our trajectory and our strategy to this event,” McGovern said. Before the crack was reported, officials had already discussed a temperature at which they would evacuate emergency responders and chemists from the site, while Craig Covey said authorities had a set temperature where the tank would be going into thermal runaway.
McGovern said the operation was necessary to avoid “the worst-case catastrophic event that we’ve been talking about,” and urged people to stay clear of the evacuation zone while crews worked through the night. “We need to run this operation tonight. Please help us. Stay out of the evacuation zone. Let us run our operation, and tomorrow we will be giving you an update on what occurred this evening,” he said. He also said, “We’re not there yet, but this was a step in a right direction.”
The crisis has unfolded days after mass evacuations were ordered in Orange County, where officials have been dealing with the volatile tank at the Garden Grove site. BLEVE stands for boiling liquid expanding vapor explosion, a violent failure that can occur when a pressurized vessel ruptures. Officials had not publicly disclosed the exact temperature that would trigger an explosion, but they had been trying to cool the tank to 50 degrees while keeping the area safe around it.
Lee Zeldin said Sunday morning the most likely outcome was a low-volume release that local authorities could monitor, neutralize and contain. “I’m being told this morning that the most likely scenario is one of a low volume release, where the local authorities are going to be able to monitor, neutralize and contain the threat,” he said. That assessment gave crews some room to keep working, but the all-night mission showed they were still not ready to say the danger was over. If the pressure has been released as hoped, the tank may have moved out of the most dangerous phase; if not, the site remains one bad reading away from a new emergency.
