Experts trying to prevent a tank of hazardous chemicals from exploding in southern California found a “potential crack” in the container that might be reducing the pressure, a fire official said on Sunday.
Since Friday, officials have warned that the tank, which contains methyl methacrylate, a flammable chemical used in plastics and manufacturing, could rupture and spill up to 26,500 litres (7,000 gallons) of toxic material or explode and endanger other tanks on the GKN Aerospace site.
Evacuation orders were issued on Friday for an area in Garden Grove, a suburb roughly 48km (30 miles) south of Los Angeles. Tens of thousands of people are covered by the evacuation orders.
T.J. McGovern, interim fire chief of the Orange County Fire Authority, said in a video message posted on social media that a team of specialists on Saturday night found “a potential crack in the tank, which could potentially be relieving some of the pressure in there”.
Discovering the potential crack was “positive intel”, McGovern said.
Authorities are still trying to determine whether the possible crack has relieved pressure in the tank, a spokesman for the Orange County Fire Authority told Reuters. Lowering the pressure could help avert an explosion, he said.
Although officials for now are focused on measuring pressure, the spokesman said, the crack eventually could allow authorities to gradually drain the chemicals.

