Tuesday, Aug. 27, 2013 | 4:05 p.m.
A foamy white substance bubbling up out of storm drains in the northwest valley for the past two days is the result of fire retardant used to battle the fire on Mount Charleston last month that was washed into the valley as a result of this weekend’s rain, local officials said Tuesday.
Retardant residue — a mixture of mostly water and fertilizer — remained on the mountain after crews spent two weeks battling a massive fire there in July.
Foam began pouring out of storm drains Monday in a residential area near Ackerman Avenue and El Capitan Way in Las Vegas, creating a sudsy mess that was roughly 20 feet long and 10 feet wide, city spokesman Jace Radke said.
“Basically, there are two pipes that come together there and one of them is smaller than the other,” Radke said. “The water being pushed through created a sort of washing machine effect.”
City crews had the foam cleaned up early Tuesday and put down sandbags to keep it from seeping back up, Radke said.
The fertilizer residue did not make it into the sanitary sewer system and no people were threatened by the runoff, Radke said.
Officials at the Southern Nevada Health District have contacted the United States Forest Service to ensure the runoff didn’t pose a threat and were informed that the retardant mixture, which contains about 10 percent ammonium phosphate, is “practically nontoxic,” said Dennis Campbell, environmental health manager for solid waste and compliance at the health district.