A fast-moving Sandy fire burning near the Santa Susana Field Laboratory in Simi Valley has prompted air monitoring around the blaze after officials raised concerns about what could be released if it reaches the cleanup site. Fire crews said the lab has not bee
The Sandy fire pushed into the hills near Simi Valley. and for residents watching from nearby neighborhoods. the danger wasn’t only the flames. It was what sat a short distance away: the Santa Susana Field Laboratory. a 2. 850-acre complex that has a history of toxic waste and a partial nuclear meltdown.
Late Wednesday. the Ventura County Fire Department said air quality monitoring was being conducted around the fire’s perimeter because of the blaze’s proximity to the Santa Susana Field Laboratory. The monitoring effort is meant to establish a starting point—so that if the fire advances into the sensitive area. officials have a baseline to compare against.
Ventura County Fire Department spokesperson Andrew Dowd said monitoring had been “deployed to establish a background air quality. so that if the fire advances further into that sensitive area we would have a baseline to compare against.” He added that the fire had not yet reached the field laboratory area and that crews were making strong progress containing the blaze.
By 3:30 p.m. Thursday, the fire had burned 2,141 acres and was 30% contained. At that point, several evacuation orders and warnings were downgraded. By nightfall, containment increased to 40%.
Dowd said conditions were shifting in a way firefighters welcomed. “Today we’re experiencing lower winds and higher relative humidity, so we’re seeing reduced fire behavior,” he said. “Because of that, the risk of the fire spreading in any direction is less than it was before.”
The fire’s location raised an additional concern for emergency teams: the field laboratory is currently in an evacuation warning zone to the east of the Sandy fire.
The Department of Toxic Substances Control. which oversees environmental remediation of the Santa Susana site. said it is working closely with local and federal agencies to monitor the incident and potential impacts to communities near the laboratory site. In a statement. the department said. “To ensure we are aware of any off-site impacts. the emergency response team has deployed air monitors to support response efforts and safeguard public health.”.
Boeing, which owns the Santa Susana site, said it had evacuated all personnel. The company also said it was working in coordination with local authorities and emergency responders as conditions changed around the facility.
The fire department also emphasized how it views the threat tied specifically to radiation. In a Thursday evening statement. it said the laboratory sits in a historically wildfire-prone area. but maintained there was limited need for concern about the possible release of radiation. The department pointed to radiation measurements collected as recently as 2025, along with modeling conducted following the 2018 Woolsey Fire.
“The radiation measurements collected as recently as 2025. along with modeling conducted following the 2018 Woolsey Fire. continue to indicate that the extremely low levels of residual radioactive material at the site pose no risk to public health. even in the event wildfire activity reaches the area. ” the department stated.
Health officials said there was no increased risk to the public beyond what is normal for wildfire smoke. according to the fire department and its reporting. Testing by the Department of Toxic Substances Control found no radiation levels above background and no hazardous compound levels other than those normally present after a wildfire.
Still, the lab’s history keeps the public alert. The Woolsey fire originated at the Santa Susana Field Laboratory and swept through a significant portion of the site. After Woolsey. the Department of Toxic Substances Control found no radiation levels above background. and no hazardous compound levels other than those normally present after a wildfire. Yet a study published in 2021 found evidence of radioactive waste in a limited number of soil samples collected after the Woolsey fire.
For some people living near the laboratory, that history—plus the Sandy fire’s proximity—has made the situation feel personal.
During the 1950s and 1960s. workers would regularly burn toxic waste in open pits and cleaned engines with solvents that later contaminated the groundwater. In 1959. there was a partial meltdown of the core in one of the lab’s nuclear reactors. an event considered among the worst nuclear accidents in U.S. history.
The site’s legal legacy also looms. In 2005. Boeing agreed to pay $30 million to settle a lawsuit alleging that pollutants from the hilltop lab were responsible for a variety of cancers. autoimmune disorders and tumors afflicting nearby residents. A 2006 study found that radiation at the site may have contributed to hundreds of cases of cancer in the surrounding community. Since then, activists have continued to document cases of cancer found in residents living near the site.
Right now, the immediate fight is containment—2,141 acres burned as of 3:30 p.m. Thursday, 30% contained at that time, and 40% contained by nightfall—while air monitors gather data around a facility many in the area view through the lens of what happened during earlier disasters.
Fire crews say the field laboratory has not been reached yet. and officials insist that radiation levels remain extremely low and that conditions causing smoke risks are what the public should expect in the near term. But the monitoring itself. and the careful language around baselines. reflect what people near the Santa Susana site have lived with for years: fear that a wildfire can turn old contamination into a new problem.
As containment improved and winds eased, the question moved from whether the fire could be stopped to whether the data collected at the perimeter will remain just that—data—and not the start of another, deeper chapter for communities already wary of the hills they can’t escape.
Sandy fire Santa Susana Field Laboratory Simi Valley air monitoring toxic waste nuclear meltdown Boeing Ventura County Fire Department evacuation warnings Department of Toxic Substances Control Woolsey Fire