An industrial tank in Southern California containing about 7,000 gallons of a highly flammable toxic chemical appears to have cracked, officials reported on Sunday. The development was interpreted as a possible sign that a catastrophic explosion or rupture might yet be averted as tens of thousands of evacuees waited to return home.<\/p>\n
TJ McGovern, the interim fire chief of the Orange County Fire Authority, said in an update that firefighters conducted a \u201csuccessful operation\u201d on Saturday night to inspect the tank at a plant in Garden Grove that belongs to U.K.-based GKN Aerospace, which manufactures aircraft components.<\/p>\n
The container became increasingly pressurized on Thursday, heating the chemicals inside and releasing gas that could trigger an explosion. Firefighters responded, dousing the tank with copious amounts of water in an attempt to cool it. But GKN Aerospace\u2019s team was unable to inject a neutralizing agent to reduce the chemical\u2019s instability because of several failed valves.<\/p>\n
\u201cNo one has ever had this situation before because the chemical is so volatile,\u201d Chief McGovern said. He called the situation \u201cunprecedented.\u201d<\/p>\n
The chemical inside the tank, methyl methacrylate, is used in the manufacture of resins and acrylic plastics, most notably plexiglass.<\/p>\n
According to the Environmental Protection Agency, exposure to methyl methacrylate can irritate the eyes and skin and make it difficult to breathe, among other symptoms. Birth defects have appeared in exposed animals.<\/p>\n
On Saturday, local fire officials said the temperature inside the tank had risen more than 20 degrees and was still rising. By Sunday, it had reached at least 100 degrees.<\/p>\n
There is fear of a \u201cthermal runaway,\u201d which could further generate heat, build pressure and cause a blast, said Elias Picazo, an assistant professor of chemistry at the University of Southern California.<\/p>\n
Alternatively, he said, a tank failure \u2014 in which the tank ruptures but does not necessarily explode \u2014 could lead to a controlled leak that could then be neutralized.<\/p>\n
\u201cI think the temperature within the tank has been steadily increasing and that\u2019s indicative that the reaction is moving forward,\u201d he said.<\/p>\n
It is possible, officials said on Saturday, that the increase in temperature is occurring because the liquid inside the tank is solidifying. If so, and if the tank holds, that could make a rupture less likely.<\/p>\n
A specialized team of officials from the fire departments in Los Angeles, San Bernardino County, Orange County and Long Beach were working on alternative solutions to prevent the tank from breaching, Chief McGovern said on Sunday.<\/p>\n