This week's storm dropped nearly half an inch of rain on the Tustin area, and more is on the way — that’s good for dampening smoke from the fire that continues to slowly consume a World War II era hangar on the former Marine Corps base there.
But what about for containing the asbestos, arsenic and other toxins released by the hangar fire?
LAist spoke with officials and public health experts who agreed rain is generally good for cleaning toxins from the air and ground, though it could cause other, likely minor, concerns down the line.
The status of the hangar and cleanup
Officials said in a news release late Wednesday that they had finished cleaning up debris in the immediate vicinity of the hangar — even though they had to stop work early because of lightning. They also said large catch basins around the hangar would collect rain runoff from the still smoldering building.
Most of the massive building — 17 stories high and more than 1,000 feet long — has already collapsed. Officials said that as of Thursday night, 30 to 50 feet of the western facing wall was left standing.
[Listen: Members of the Marine Corps community share their memories of the Tustin blimp hangars on AirTalk.]
Ryan Coe, spokesperson for the fire’s incident management team, said they plan to take down the metal framed doors in the near future. The concrete pillars that frame the doors will remain, Coe said.
"So the public's not going to see some big wrecking ball hitting these concrete pillars and knocking down a bunch of concrete," he said.
Clean-up crews were focusing on neighborhoods north of Edinger Avenue on Wednesday, officials said. Coe told LAist that the hotline set up earlier this week for residents to report debris had received 152 calls on Tuesday, its first full day in operation.
You can reach the hotline by calling (714) 426-2444. Residents can also report debris online.
Lt. Andy Birozy, spokesperson for the Tustin hangar fire incident management team, said that as of Thursday the hotline had received 369 calls. Between the online debris-reporting portal and hotline, officials had taken 692 total requests as of Thursday.
Air quality status
The South Coast Air Quality Management District (AQMD) has been monitoring air quality and testing debris from the fire. Most air quality samples have shown no elevated levels of heavy metals. But inside the smoke plume, some elevated levels of lead and arsenic have been detected.
It's unclear just how far and wide debris from the fire may have spread, given changing wind patterns in recent weeks. The Tustin Unified School District has published a map showing that 14 schools in the district found at least one piece of debris from the fire on their campuses, along with two other schools that are in close proximity to the burn site.
Debris was found as far north as Estock Elementary, north of Irvine Boulevard, and as far east as Beckman High School north of I-5. Both are about 4 miles from the burn site.
According to the AQMD's latest report, air samples collected Nov. 12 at fixed monitors in the surrounding community did not detect any asbestos. (You can view all of the AQMD's reports from the Tustin hangar fire here.)
Michael Kleinman, a public health professor at the University of California, Irvine, said the rain would likely help lower emissions from the fire and reduce any toxicity.
"Rain is really very efficient at cleaning particles out of the air," he said.
Still, he said anyone near the smoke plume should take extra precautions. He said people living near the burn site with children should make sure kids are keeping their hands clean and not touching ash or debris from the fire because they're more prone to "getting hand to mouth kind of contamination."
What about soil and water?
Roy Herndon, chief hydrogeologist at the Orange County Water District, said the rain could help remove toxic ash and debris from the places where people are most likely to have direct contact with it.
"Thinking of ball fields, playgrounds, roofs, parking lots, walkways — all the things throughout the area that might have been affected [by fire debris] may get a flushing," he said.
Of course, that water has to go somewhere — mostly into storm drains. Herndon said some of the main drainages in that area include Peters Canyon Wash and Barranca Channel, which feed into San Diego Creek and then Upper Newport Bay.
Shannon Widor, spokesperson for Orange County Public Works, said the department regularly carries tests water in flood channels during and after rainstorms.
The Orange County Health Care Agency advises people to stay away from storm drains and creeks, and out of the ocean for three days after rain.
Are there risks to the water supply?
Herndon said it's very unlikely that toxins from the fire ash could make their way into groundwater used for drinking.
"Ash is a particle, it's a particulate, and particulates tend to be filtered out fairly readily as water percolates through soil," he said.
The Navy has acknowledged that groundwater under the former base is contaminated. But that water isn't used for drinking — rather, drinking water is supplied to the area by the Irvine Ranch Water District.
Greg Pierce, who directs the Human Right to Water Solutions Lab at the University of California, Los Angeles, said he has confidence in local water suppliers and official monitoring bodies to manage any potentially toxic effects from the fire on the water system.
"The Irvine Ranch Water District is incredibly sophisticated when it comes to drinking water quality," Pierce said.
He added that the volume of toxic sediment that could reach waterways is likely small and diffuse and, therefore, unlikely to have a big impact on surface water quality.
