As the threat of a chemical tank explosion in Garden Grove dragged into its third day, officials announced a potentially positive new development — a crack was seen on the tank.

Tens of thousands of residents have been evacuated and Gov. Gavin Newsom has declared an emergency as officials try to thwart an explosion at the facility in Orange County.

In a joint statement from the city of Westminster and the Westminster Police Department, officials described the situation as “critically positive.”

Emergency crews launch overnight mission to neutralize a volatile chemical tank at a Southern California aerospace facility in Garden Grove as Gov. Gavin Newsom declares state of emergency.

As officials in Southern California race to cool down a massive tank filled with a toxic chemical at risk of explosion, tens of thousands of nearby residents have been forced to leave their homes due to health concerns and the risk of catastrophic damage if there is a blast.