Updated at the bottom with news that the owner had been cited by California workplace health authorities in the past. First posted at 4:43 p.m.

A large explosion seriously injured at least four people and took out a good part of a commercial building in Pacoima today, according to the Los Angeles Fire Department.

The blast at a business at 12825 Arroyo St. 12349 Gladstone Ave. was reported at 4:20 p.m.

ABC7 news reported that a triage area has been set up there and that an urban search and rescue team was en route to free possibly trapped employees.

The station reported that two people might be missing as a result of the blast.

Our Google Maps view shows that the blast was near CPR Trucking Inc., the Adult Factory Outlet and Fantasy Cookie.

Added: The LAFD reports that two CNG compressed natural gas tanks might or might not be the culprits.

ABC7 says two or maybe three patients were taken to hospitals; one apparently sustained minor injuries.

Update: The LAFD's Brian Humphrey states that two males have been seriously injured and were taken to trauma centers. A third person, gender unknown, appeared to have sustained only minor injuries, he said.

Update No. 2: ABC7 reported that one those critically injured was an LAFD firefighter on disability named Tim Larsen who worked at the business. The station reported that he lost an arm and a leg in the blast.

His brother is said to have died in a similar natural gas explosion last year.

The station said the address was the site of an “alternative fuel technology” business. CBS 2 stated that some believed the place was purifying water for Third World countries.

Also: Is it Pacoima or Sylmar or Lakeview Terrace? We don't know. Not our barrio. Most initial accounts had it in Lakeview Terrace. We took a look at our Thomas Bros. map and put it in Pacoima. Now most outlets are saying Sylmar. It's close.

Update No. 3: The California Division of Occupational Safety and Health cited the owner of the business, Realm Catalyst Inc., following the June 17, 2010 explosion at a different site that took the life of the firefighter's brother. These alleged violations were listed, according to a document forwarded to the Weekly:

Failing to have permits to operate pressure vessel tanks; using an out-of-compliance tank; and failing to adequately maintain a tank.

We were told by Cal/OSHA spokeswoman Erika Monterroza that a hearing in the matter

had just taken place Monday.

Meanwhile KNX 1070 Newsradio reported today that a criminal investigation into the blast was now underway.

City News Service reports that it was Larson's 28-year-old brother, Tyson, who was killed in June, 2010.

Humphrey of the LAFD said the site was part of “an alternative fuel business involved in the extraction of hydrogen from water.''


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