An emergency related to a leak in a chemicals tank in the US state of California appeared to ease on Monday.
Orange County Fire Authority acting chief TJ McGovern said in a video update that "the threat [of a chemical explosion] has been eliminated, that threat is off the table."
The temperature of the chemical, methyl methacrylate, had stabilized and was falling, fire officials said.
An apparent crack in the tank had previously raised hopes that it could reduce the internal pressure. Emergency crews inspecting the tank during the night confirmed the crack and found that the temperature had fallen from 100 degrees Fahrenheit (about 37.7 degrees Celsius) to 93 degrees Fahrenheit (about 33.9 degrees Celsius).
Fire Authority personnel had been deployed for days to deal with the emergency. About 50,000 people living in the so-called danger zone around the town of Garden Grove were forced to leave their homes and spend the weekend in hotels, emergency shelters or even in their cars.
The evacuation zones remained in force, McGovern said. He described the potential chemical explosion as a "BLEVE", a "Boiling Liquid Expanding Vapour Explosion."
A leak could also pose significant risks, however, as methyl methacrylate is highly flammable and could also cause environmental damage.
