A man trying to get rid of a gopher ignited a 7-acre brush fire on his property in Brentwood on Friday afternoon.

No one was injured in the blaze, which blackened a hillside in the 9600 block of Deer Valley Road. Firefighters from the East Contra Costa and Contra Costa fire districts and Cal Fire battled the blaze, and a Cal Fire helicopter made water drops.

“The man was trying to get a smoke bomb to go off and had some problem when he struck the match,” said East Contra Costa Fire Protection District Marshall Steve Aubert. “We would like to take the opportunity to remind everyone to be mindful of their conditions and this early season fire should be a reminder of what can happen very quickly.”

Firefighters said they did not know what happened to the gopher.

Steve Rubenstein is a San Francisco Chronicle staff writer. Email: srubenstein@sfchronicle.com