Some 40,000 residents in southern California were under evacuation orders on Friday as local authorities were trying to mitigate a toxic chemical leak from a storage tank on the premises of an aerospace company.
Authorities have been at work to prevent the tank, which contains the chemical methyl methacrylate and is located at an aerospace facility in Garden Grove south-east of Los Angeles, from exploding since it began leaking on Thursday afternoon and started to overheat.
California state senator Tony Strickland referred to the situation as a "massive industrial chemical leak incident" following a briefing with public safety officials.
Craig Covey, of the Orange County Fire Authority (OCFA), on Friday said that a team was at work "to figure out how to fix this" and prevent the tank from cracking or exploding.
Meanwhile, the tank was being cooled externally with water to prevent further heating. A faulty valve caused additional problems.
The chemical is highly toxic and flammable, Covey said. The liquid is used in the production of plastics.
Orange County's health officer Dr Regina Chinsio-Kwong said that when the substance heats up it causes a vapour that, if inhaled, can "significant irritation" to the lungs and nasal passages, as well as dizziness and nausea.
Prolonged exposure can cause "severe respiratory issues," Chinsio-Kwong said, explaining that that was why authorities issued evacuation orders for an area covering approximately 23 square kilometres.
