Wildfire crews in Southern California are racing to stop a fast-moving blaze from reaching one of the country’s most contaminated former nuclear and rocket testing sites. The Sandy Fire, burning in Ventura County since Monday, moved within about a quarter mile of the closed Santa Susana Field Laboratory as firefighters faced hot, windy weather this week.

The fire had burned almost 1,700 acres by Wednesday morning and was only 15 percent contained, according to CAL FIRE. Officials ordered evacuations for over 43,700 people in Simi Valley, and hundreds more were under evacuation warnings.

Firefighters defend former nuclear site

The Santa Susana Field Laboratory (SSFL), once used for aerospace and nuclear research, has not been used for years, but cleanup work is still underway. Firefighters are concentrating on protecting the area as the Sandy Fire spreads through dry brush and steep terrain.

“We are very aware of the importance of doing everything we can to limit the spread of fire. We have put in extensive fire control features around that facility,” Andrew Dowd, a public information officer for the Ventura County Fire Department, as reported by Gizmodo.

Dowd also said crews are trying to keep the fire from spreading in any direction, especially toward the contaminated site. Officials warned that hot, dry winds could keep affecting the fire’s path this week.

Boeing, which has owned most of the SSFL property since 1996, confirmed that all nonessential workers have already been evacuated from the site. “We are actively monitoring the Sandy Fire near the Santa Susana site and are in close coordination with local authorities and emergency responders,” the company said in a statement. “This is an ongoing situation, and as it evolves, we will continue to monitor fire conditions.”

Federal officials are also monitoring developments. The U.S. Department of Energy stated online that it “is closely monitoring the Sandy Fire located adjacent to the Santa Susana Field Laboratory.” The agency added that there is currently “no impact to the site.”

Sandy Fire grew after winds shifted

The Sandy Fire started near Simi Valley around 10:50 a.m. Pacific Time on Monday. Authorities are still investigating the cause of the blaze.

Local police told Eyewitness News that a caller reported a tractor hitting a rock while clearing brush just before the fire started. Investigators have not confirmed if this caused the wildfire.

Emergency officials said the fire calmed down overnight on Monday but grew stronger again on Tuesday when the winds changed. Reports said the new wind direction put the Santa Susana site in the path of the flames.

Ventura County Emergency Information officials emphasized on Tuesday evening that the fire had not reached the laboratory grounds. “As of Tuesday, May 19, 2026, at 5:27 pm, the fire has NOT impacted the Santa Susana Field Laboratory (aka Rocketdyne) located on Woolsey Canyon Road,” an official update stated. “Fire crews continue to prioritize protection of the area.”

Authorities have not provided updated measurements of how close the fire is to the facility because conditions are changing rapidly.

Toxic contamination raises public concern

People are worried about the wildfire because SSFL has been polluted for decades. The site has dangerous substances from rocket testing, chemical work, and the 1959 nuclear accident.

According to the California Department of Toxic Substances Control, contaminants in the soil and groundwater at the site contain petroleum hydrocarbons, industrial solvents, heavy metals, and radioactive materials. State and federal agencies, including NASA, the U.S. Department of Energy, and Boeing, are still working on long-term cleanup plans for the area. In 2024, temporary cleanup efforts removed over 6,000 cubic yards of contaminated soil.

Experts warn that if the wildfire reaches polluted parts of the site, the smoke could carry more toxic substances into nearby communities. Wildfire smoke already contains dangerous fine particles, gases, and chemicals like benzene and heavy metals.