(Bloomberg) — California firefighters could knock drones out ofthe sky when they endanger aircraft making low-altitude runs todrop water on wildfires, under a bill lawmakers proposed.

The legislation comes after unmanned vehicles forced planes andhelicopters out of the sky during a July 17 blaze that trappedpeople inside their cars on Interstate 15 in the desert northeastof Los Angeles and during a late June wildfire that scorched 31,000acres.

The bills would shield firefighters from having to pay fordrones that they down, intentionally or accidentally, as well asexpand criminal penalties and allow prison terms as long as fiveyears for pilots who hinder firefighters on federal property. Statelaw already makes it a misdemeanor to impede firefighting.

"This is intended to let firefighters do their jobs," saidSenator Ted Gaines, a Republican who co-authored some of thelegislation.

California, home to seven of the 10 most destructive fires inU.S. history, is cracking down as state and federal regulators cometo terms with the evolving technology. As many as 1 million dronesare used by hobbyists, businesses and governments in the U.S.,according to the Small UAV Coalition, a trade group.

"In just the last month, we have seen a dramatic spike in thenumber of incidents in which hobby drones have interfered with ourfirefighting aircraft," said Daniel Berlant, a spokesman for theCalifornia Department of Forestry and Fire Protection inSacramento. "We're done with the educational part of it. We'rereally stepping up and working with our law- enforcement partnersto hold those people accountable."

The Small UAV Coalition doesn't oppose the legislation, saidMichael Drobac, executive director of the group, whose membersinclude Amazon.com Inc., Google Inc., GoPro Inc. and VerizonCommunications Inc.

"We must be responsive to any kind of interference with firstresponders," Drobac said by telephone. "In the long term, thesewill prove more helpful than harmful."