Los Angeles is spraying D.E.T. to slow the spread of fires

‘Starting to look a lot better’: Rain aids Mosquito fire battle, but brings flood, mudflow risk to many areas in state

A flooded street in the foothills of the Sierra Nevada mountains in Mammoth Lakes. (Brian van der Brug/Los Angeles Times)

As part of a long-term reforestation project, a tree is planted in the backyard of Robert S. and Virginia Thomas, a Long Beach couple, on Mother’s Day. (Michael Robinson Jr./Los Angeles Times)

In late January, the Los Angeles Department of Water and Power began spraying a low-risk chemical called D.E.T. that slows the spread of fire.

But the chemical can also have a detrimental impact on the ecology, so the agency will be applying it in more localized bursts, on and off, in the coming months.


“They still have spraying on every three days,” said Scott Tousley, L.A.’s public information officer. “These chemicals don’t evaporate off, so it’s still there.”

So far, the city has already applied D.E.T. at four locations: the L.A. River, South Los Angeles River, Arroyo and Coyote Creeks in the western sections of the city, and in the foothills of the Sierra Nevada in Mammoth Lakes.

Troubleshooting the D.E.T. program

From the perspective of city officials, the D.E.T. program is one of the last steps before the city can begin restoring habitat and reforest areas burned in the recent drought.

The program was designed to reduce the amount of chemical needed to treat vegetation. D.E.T. is sprayed on brush and vegetation to protect nearby water supplies. It is most commonly used on brush that has died or been removed because of drought or other factors.


“It’s an environmental service,” Tousley said. “The goal was to reduce the amount of chemical needed.”

As a fire-fighting strategy, D.E.T. is particularly effective against dry brush

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