An organisation of physicians fear radioactive waste could become a major issue after southern California’s huge wildfire burned near a former nuclear test site.

The organisation of Physicians for Social Responsibility said it was likely that smoke and ash from the fire spread radiological and chemical contamination that was in soil and vegetation near the Santa Susana Field Laboratory.

“We know what substances are on the site and how hazardous they are. We’re talking about incredibly dangerous radionuclides and toxic chemicals such a trichloroethylene, perchlorate, dioxins and heavy metals,” Dr Robert Dodge said in a statement.

“These toxic materials are in SSFL’s soil and vegetation, and when it burns and becomes airborne in smoke and ash, there is real possibility of heightened exposure for area residents.”

Wildfires spread across California – in pictures Show all 32 1 /32 Wildfires spread across California – in pictures Wildfires spread across California – in pictures Firefighters battle a blaze at the Salvation Army Camp in Malibu Getty Wildfires spread across California – in pictures Flames from the Camp fire burn near a home atop a ridge near Big Bend AFP/Getty Wildfires spread across California – in pictures Cathy Fallon (centre) who stayed behind to tend to her horses during the Camp Fire, embraces Shawna De Long (left) and April Smith who brought supplies for the horses Reuters Wildfires spread across California – in pictures A helicopter drops flame retardant on a wildfire in Malibu Getty Wildfires spread across California – in pictures An air tanker drops water on the fire along the Ronald Reagan Freeway in Simi Valley AP Wildfires spread across California – in pictures An abandoned car from fleeing residents of Paradise in the Pentz road area EPA Wildfires spread across California – in pictures A firefighter tackles the fire along the Ronald Reagan Freeway in Simi Valley AP Wildfires spread across California – in pictures A Jack In The Box fast food restaurant burns as the Camp fire moves through Paradise, California AFP/Getty Wildfires spread across California – in pictures Yuba and Butte County Sheriff officers label a body bag AFP/Getty Wildfires spread across California – in pictures Firefighters hose down trees on Bell Canyon Road, near Malibu AFP/Getty Wildfires spread across California – in pictures A fire burns at the Salvation Army Camp Getty Wildfires spread across California – in pictures A firefighting DC-10 makes a fire retardant drop over a wildfire in the mountains near Malibu Canyon Road AP Wildfires spread across California – in pictures A house burns in Paradise, California AFP/Getty Wildfires spread across California – in pictures Bins have melted and ballooned in the heat in Magalia, Butte County EPA Wildfires spread across California – in pictures Satellite image taken on 8 November shows plumes of smoke from the Camp Fire stretching across portions of Northern California AFP/Getty Wildfires spread across California – in pictures Firefighters battle the Camp Fire AP Wildfires spread across California – in pictures Firefighters battle the Woolsey Fire Reuters Wildfires spread across California – in pictures Deputy Coroner Justin Sponhaltz, of the Mariposa County Sheriff's Office, recovers human remains found at a home destroyed by the Camp Fire AP Wildfires spread across California – in pictures Buildings burn in Paradise, California EPA Wildfires spread across California – in pictures Local residents bring their horses to Zuma Beach and away from the Woolsey Fire in Malibu Reuters Wildfires spread across California – in pictures A used car dealership burns in Paradise, California Reuters Wildfires spread across California – in pictures Yuba and Butte County Sheriff officers inspect a burned vehicle after discovering remains nearby in Concow AFP/Getty Wildfires spread across California – in pictures Firefighters battle the flames in Thousand Oaks Reuters Wildfires spread across California – in pictures A house burns in Paradise, California AFP/Getty Wildfires spread across California – in pictures A house burns in Paradise, California AP Wildfires spread across California – in pictures Search and rescue teams work to evacuate patients from the burning Feather River Hospital in Paradise, California AFP/Getty Wildfires spread across California – in pictures Embers blow in the wind in Paradise, California AFP/Getty Wildfires spread across California – in pictures In Butte County, the sky is filled with the smoke of the Camp Fire EPA Wildfires spread across California – in pictures Firefighters at work in Thousand Oaks Reuters Wildfires spread across California – in pictures A house burns in Paradise, California AP Wildfires spread across California – in pictures The burned remains of a house and car are left after the Camp Fire in Paradise, California AFP/Getty Wildfires spread across California – in pictures A shop burns in Paradise, California AFP/Getty

Regulators in California said initial testing found no elevated levels of radiation of hazardous compounds after the blaze near the site.

The Department of Toxic Substance Control said its staff went to the Santa Susana Field Laboratory on Saturday and found facilities that previously handled radioactive and hazardous materials were not affected by the fire.

The state agency said its measurements on the site and in the surrounding community found no radiation levels above background levels and no elevated levels of hazardous compounds other than those normally present after a wildfire.

In an update to their previous statement, the Organisation of Physicians for Social Responsibility said it was “irresponsible to claim that SSFL contamination was not spread further by the fire”.

Night vision military drone shows Camp Fire tearing through California

The Santa Susana Field Laboratory was used for decades to test rocket engines and for nuclear energy research.

One of its nuclear reactors had a partial meltdown in 1959, when nuclear material was intentionally vented to prevent the site’s “Sodium Reactor Experiment” from overheating and exploding.

Battles over decontamination efforts have gone on for years, with neighbours blaming the site for illnesses.

The so-called Woolsey Fire in southern California has killed two people, destroyed more than 400 structures and at its height displaced about 200,000 people in the mountains and foothills west of Los Angeles.

Meanwhile, Northern California is beset by its most deadly wildfire in history, dubbed the Camp Fire, which has killed at least 48 people, some burned beyond recognition.