Explosion planned in Sylmar

Federal environmental officials were planning to detonate at least one canister of highly volatile gas at a Sylmar industrial park early Sunday and were set to shut down a portion of the 210 Freeway as a safety precaution.

Authorities say that a canister of gas, a mixture of oxygen and hydrogen, is too volatile to move. Instead it will be exploded on site at Rainbow of Hope, an alternative energy company at 12349 Gladstone Avenue.

An August explosion at the building ripped a hole in the roof and blew two workers onto the street, officials said. One of them, Timothy B. Larson, sustained critical injuries in the blast. A similar explosion in June 2010 at a Simi Valley facility being operated by Larson’s father, Timothy A. Larson, killed his brother, Tyson Larson, 28.

The family-owned business, which has also operated under the name Realm Industries and Realm Catalyst Inc., is the subject of inquiries by Cal/OSHA and the Environmental Protection Agency into whether the company had proper permits and stored chemicals and explosive gases properly. Los Angeles arson investigators are also looking into the Aug. 9 blast.

On Friday, businesses and residents in the vicinity of the plant were notified about the impending detonation. Officials expect little or no damage from the explosions, which will be triggered by a charge placed on the canister by a Los Angeles police bomb squad, said Nahal Mogharabi, an EPA spokeswoman.

As many as three canisters will be detonated, but some of them may be empty, she said.

“Finding out is too dangerous and is the reason they are being intentionally ruptured tomorrow,” Mogharabi said.

A total of 23 canisters of pressurized chemicals and gases remained after the August explosion, and the EPA was called in to help remove them as safely as possible, said Harry Allen, an EPA section chief for the region that covers Southern California. Six are still on site, including as many as three that contain the explosive hydrogen mixture, officials said.

Residents of Lake View Terrace and other nearby communities may hear the explosion, set for 6:30 a.m., but should not worry, the Los Angeles Police Department said in a press release. As a precaution, the 210 Freeway, about 600 feet south of the blast site, will be closed for up to several hours beginning at 6 a.m. between Maclay Avenue and the 118 Freeway.

A parallel section of Foothill Boulevard will also be closed, the California Highway Patrol said.

Larson patriarch Timothy A. Larson has been involved in alternative energy for several years, at some point bringing his sons into the business. A few months after his death, Tyson Larson was granted a patent for a process he and a co-inventor named William A. Stehl said could create energy from water molecules by using an electrical circuit to create resonance in the molecule. The energy they created, they said, could be used to power motorized vehicles.

Stehl was indicted last year in U.S. District Court in northern New York on allegations he sold investors on a similar process to create energy from water. The indictment alleged that Stehl and a co-defendant used the money for personal expenditures.

catherine.saillant@latimes.com