It rained a cheery lollipop pink on a Windsor neighborhood Thursday under cloudless sunny skies.

A Cal Fire air tanker unintentionally dropped fire retardant during its landing approach at the Sonoma County airport painting roofs, lawns and cars a reddish pink hue.

“I heard a plane go by then it started raining,” said 12-year-old Brianna Henry, who was coloring near her bedroom window. “I thought it was strange because it was a really sunny day.”

She looked outside, noticed her neighbor’s roof was pink and ran downstairs to tell her dad.

The Cal Fire air tanker was returning from a grass fire in Penngrove about 12:30 p.m. when the pilot, for reasons still under investigation, released about 100 gallons of water mixed with Phos-Chek, a material with a mild fertilizer designed to both stop the fire’s spread and encourage regrowth, Cal Fire Division Chief Ben Nicholls said. The tanker carries 1,000 gallons.

The pink stuff rained upon nine homes, 13 vehicles, a travel trailer, the street, sidewalks, grass, shrubbery and trees along Decanter Circle near Windsor High School.

Parked next door to the Henry home, Veronica Mora’s white car was unrecognizable with its new cherry shade.

“Who would have thought this would happen?” Mora said.

Windsor city staff used materials and a vacuum truck to prevent retardant from going down storm drains and are monitoring nearby creeks, said Elizabeth Cargay, environmental program manger for the town.

“It’s pretty harmless, but anything but water is considered a substance that shouldn’t go down the drain,” Rincon Valley Battalion Chief Matt Gustafson said.

Firefighters washed the vehicles and cleaned the road. Nicholls said the material is safe to let be on the roofs. Lawns and gardens might just grow a little greener.

“As firefighters, we get dropped on all the time,” Nicholls said. “It’s practically nontoxic.”

You can reach Staff Writer Julie Johnson at 707-521-5220 or julie.johnson@pressdemocrat.com. On Twitter @jjpressdem.