The wildfire became the second most destructive fire in California's history, killing 19 and destroying 9,000 buildings.
"We were having trouble sleeping," he said of his team. "Chronic cough, headache, fatigue - just a really rough set of symptoms following the fire."
"I felt much better immediately after the worst exposure of my career," said Marquez, a 25-year veteran of firefighting, who has battled with health issues for years.
"We were so desperate because of how messed up we were. We were willing to pretty much try anything," he said.
Scientists have long known that inhaling toxic smoke from a fire can cause a huge range of illnesses, including several types of cancers. First responders, like firefighters, are especially susceptible. Firefighters have a 14% increased risk of dying from cancer, external compared to the general American population, according to the US National Institute for Occupational Health and Safety.
And as awareness of the risks evolve, so too has interest in alternative - but often unproven and potentially dangerous - treatments.
Glutathione, an antioxidant that is naturally produced inside the human body, has been offered as a treatment at some of the largest US wildfires in recent years – including most recently in Spokane, Washington. Anecdotal evidence gathered by clinicians and fire departments has shown promising signs that it could be used to rid firefighters of some of the cancer-causing chemicals they absorb during fires. However, no large-scale research has yet been conducted on its safety and efficacy, and there are concerns over purity and contaminated supplies.
The International Association of Fire Fighters (IAFF) issued a rare warning about glutathione last month. It noted two recent recalls due to contaminants at compounding pharmacies that produce glutathione. It also noted scientific trials of other common, naturally-occurring vitamins that were found to increase – rather than decrease – the risk of cancer, although none of those vitamins are used in glutathione treatment.
"We don't know if glutathione is affective," said Sean DeCrane, the assistant to the general president for health and safety at the IAFF, which represents over 360,000 firefighters across the US and Canada.
"We don't know if it's a placebo effect. We don't know the long-term effect of this type of treatment."
DeCrane said his group opposes the way it has been "marketed" to firefighters, including in Spokane where morning briefings fire chiefs to their crews included suggestions that they visit a volunteer tent for treatment.
"The lack of research really raised concerns for us," he said. He adds that the IAFF has spoken to "multiple members who said that they did not feel well after the treatment, [and] that they felt worse."
"The clinician told them, 'Oh, that's just those metals leaving your body'," he said.
The recent rise of glutathione can be traced back to 2017, when a group of naturopaths formed together in Santa Rosa, California, to provide assistance to fire crews combating the Tubbs Fire.
The Integrated Health Action Network (IHAN), previously called the Integrative Healers Network, now sends volunteer clinicians to major wildfires across the country to provide glutathione, as well as other naturopathic treatments including acupuncture and massage therapy.
In response to the warning from IAFF, the group released a statement agreeing with the need for further testing, and offering to work with researchers to prove glutathione's effectiveness.
Co-founder Jen Riegle, who is not a medical doctor but is a licensed naturopath, external, said that glutathione treatment often leads to "clinically-meaningful improvements in headaches, fatigue and brain fog, which are some of the top symptoms we see in firefighters when they're on a fire". The treatments help to force out some of the harmful contaminants in firefighters' bodies, she claims, and can have short-term side effects immediately after treatment.
Riegle is hopeful the data the group has collected will spur on further research, and "to prove that this is a good long-term solution for firefighters". But she adds that all of the evidence IHAN has collected is anecdotal, and far from conclusive.
"I just want to be really clear that what we are collecting is data that we have because of a treatment programme," she said.
"It shouldn't ever be misconstrued as clinical trial data, or double-blind, placebo-controlled, peer-reviewed data. It is just meant as a starting point to be able to garner support for future studies." Medical trials of a new drug typically take years before receiving regulatory approval, and involve rigorous a research and standards.
Interest in glutathione rose last year when California's state Board of Pharmacy attempted to pass new rules that would have severely restricted its production.
The proposed rule change led to a groundswell of opposition from some firefighters, who travelled to the state capital to testify about how it has improved their health. The plan to further restrict it was later abandoned.
Marquez was among the firefighters who went to Sacramento to testify in uniform. He said he is grateful that glutathione is being offered more frequently – including by all fire stations in Pasadena, where he works.
He dismisses concerns about its effectiveness, including suggestions that alleviated symptoms could be due to a placebo effect.
Using an expletive, Marquez said: "I don't [care] it's a placebo - it was working. Guys were saying they felt better. I felt better. And it made me want to seek out more treatments."
Regulations and medicines for firefighters have at times lagged behind the need. Until last year, firefighters for the National Forest Service were banned from wearing face masks due to concerns about their ability to operate in rugged mountain terrains. There is now a growing understanding of the need for respiratory protections and decontamination to help prevent certain cancers that are more common for firefighters.
Dr Coralynn Sack, an occupational pulmonologist specialising in air pollution's effects on the body at the University of Washington, said the noxious fumes from wildfires are well known to pose "inhalational hazards" to firefighters.
"There's been a lot of interest in using antioxidant supplements for air pollution in general," she said. "Studies have shown mixed responses. Some have even shown worse responses."
Sack said there was "biological plausibility" to think such a treatment might work, but said she was "very underwhelmed by the data that exists". There have been no clinical trials on glutathione in firefighters, she added.
Sack said the debate over glutathione "shifts the emphasis away from things that we know work" like giving firefighters access to good personal protective equipment. %!s()