Steve Aubert, Fire Marshal for East Contra Costa Fire Protection District, says it happened around 2:30 Friday afternoon off the 9000 block of Deer Valley Road.
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The Contra Costa Fire Department and Cal Fire assisted East Contra Costa Fire Protection District. Crews were able to contain it to 7 acres.
"The gentleman was trying to use some measures to eradicate some of the ground squirrels," Aubert said. He said in the process of lighting the smoke bomb, that's what ended up igniting the fire.
Aubert said no structures were threatened and no one was injured.
But fire officials want this incident to serve as a reminder to everyone, be mindful of their conditions. Especially with the dry weather recently.
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"With the lack of rain we've been having and of course a very dry summer season we had last year some of that longer grass on the steeper part of the hillside is still dry from last year," Aubert said.