The death of a 5-year-old in a hyperbaric chamber in Michigan has prompted calls for more oversight of hyperbaric oxygen therapy in the largely unsupervised wellness industry before another tragedy occurs.

Thomas Cooper was killed Jan. 31 when a fire broke out in a hyperbaric chamber at the Oxford Center, an alternative medicine clinic in the Detroit suburb of Troy. On Monday, the Oxford Center founder and CEO and three of her employees were charged in Thomas’ death.

Hyperbaric chambers are pressurized, tubelike devices that people lie or sit in for treatment, depending on the type of chamber. The therapy involves breathing in air that consists of 100% oxygen, which helps the body heal more quickly but also creates a highly combustible environment. The treatment method has been cleared by the Food and Drug Administration to help over a dozen conditions including carbon monoxide poisoning, severe wounds and decompression sickness in scuba divers.

The Oxford Center’s website lists over 100 conditions it says it treats, including many that the FDA has not approved for hyperbaric oxygen therapy, such as cancer, dyslexia, Alzheimer’s, Lyme disease and autism — though it is not illegal to use hyperbaric chambers for these purposes. In a statement to NBC News, an attorney for the Oxford Center said the center was “disappointed” by the charges filed against four staff members.

“The timing of these charges is surprising, as the typical protocol after a fire-related accident has not yet been completed. There are still outstanding questions about how this occurred,” Sam Vitale said via email about Thomas’ death.

Thomas was receiving hyperbaric oxygen therapy for sleep apnea and attention-deficit/hyperactivity disorder, according to his family’s attorney, which are not among the conditions approved by the FDA for such treatment. Michigan Attorney General Dana Nessel said the boy died within seconds after a single spark started a fire in the hyperbaric chamber he was in. Officials have not said yet what the cause of the fire was.

In a news conference Tuesday, Nessel accused Oxford Center staff of holding “safety among their lowest considerations” but said officials had no way of knowing about the danger until it was too late, and cannot proactively investigate other facilities.

“Michigan law doesn’t require any oversight over the use of hyperbaric chambers, so without having some sort of probable cause to believe that there are crimes being committed involving hyperbaric chambers in other places in the state, we wouldn’t have the authority to go in and perform an inspection,” Nessel said.

The Oxford Center was subject to inspections every few years by the Troy Fire Department, said Michael Koehler, the fire department’s deputy chief. He said the center applied for a permit when it opened, indicating it would be using hyperbaric chambers, and was last inspected in March 2023.

“But our inspections are fire- and life-safety focused,” Koehler said in a phone interview Friday. “There’s nothing that covers the operation or the maintenance of the chambers themselves.”

While hospitals that use hyperbaric chambers abide by codes developed by the National Fire Protection Association, a standards development organization, Michigan is not unique in lacking a regulatory framework for hyperbaric oxygen therapy outside of traditional health care facilities, said John Peters, executive director of the Undersea & Hyperbaric Medical Society, a nonprofit organization that accredits hospitals and freestanding facilities with hyperbaric chambers in the absence of government regulation.

At the moment, nearly 150 facilities across the country are accredited by the group, with two in Michigan.

The accreditation process involves on-site inspections and verification that equipment is maintained and specialists are properly trained, and costs about $10,000 for an accreditation that lasts for three to four years, Peters said.

He estimated that thousands of spas, wellness companies and other storefronts are operating hyperbaric chambers in the U.S. without having undergone accreditation, and he said he fears many may not be upholding stringent standards.

Two Democratic legislators in Michigan, state Sen. Stephanie Chang and state Rep. Sharon MacDonell, are working together to explore regulatory options after Thomas’ death.

Chang said she was alarmed by what appeared to be a myriad of problems that led to the fire, based on what the Michigan attorney general outlined, including allegedly not having a properly trained technician operating the hyperbaric chamber.

“Let’s fix all of those loopholes,” Chang said. She said she and MacDonell are aiming to introduce legislation in the spring.

MacDonell said it was important not just to make hyperbaric chambers safer but also to stop businesses from making unproven claims about what the therapy can do.

“People are taking advantage of parents with children with hard-to-treat conditions, and just kind of monetizing the desperation of the parents,” she said. “It’s just incomprehensible.”

Thomas’ death comes as the use of hyperbaric oxygen therapy has proliferated, gaining steam in recent years thanks to celebrities who have touted it for everything from anti-aging to boosting their mental health. The FDA has warned that some claims about what hyperbaric chambers can do are “unproven” and encourages patients to only go to accredited facilities.

Hyperbaric chamber fires are rare, but not unprecedented. In 2009, a 4-year-old and his grandmother died after a blaze at an unaccredited Florida clinic where the boy was receiving treatment for cerebral palsy. Two staff members were charged in their deaths, one of whom was a doctor who lost his medical license.

The 2009 case did not prompt national safety regulations, Peters said. He is hopeful that Thomas’ death will.

“We desperately need mandatory accreditation,” he said. “We’re hoping that this will turn the page.”

While there are guidelines for how to safely construct and operate hyperbaric chambers, there is no consistent federal, state or local oversight of the practice outside of hospitals. The FDA said in an email last month that it regulates certain hyperbaric chambers that meet the agency’s definition of Class II medical devices, which are “intended for use in the diagnosis of disease or other conditions, or in the cure, mitigation, treatment, or prevention of disease.” But it does not regulate the practice of medicine and referred NBC News to the Centers for Medicare & Medicaid Services, The Joint Commission and state medical licensing agencies for more information.

The Centers for Medicare & Medicaid Services requires Medicare and Medicaid providers to comply with parts of the National Fire Protection Association code, but that does not apply to other facilities, which must still adhere to local building and fire codes, said Brian O’Connor, a senior engineer at the National Fire Protection Association.

The Joint Commission, a nonprofit organization that accredits over 24,000 health care programs around the world, said in an email that it has emergency procedures and training drills for hospitals that have hyperbaric chambers but does not accredit places such as the Oxford Center.

Meanwhile, Michigan’s health department, its occupational safety agency and the Department of Licensing and Regulatory Affairs all said they do not have oversight of hyperbaric chambers. The licensing agency said facilities using hyperbaric chambers are not required to be licensed, which Peters said was shocking.

“Why?” he said. “Even a hairstylist has to have a license, and she’s not going to blow up her whole salon.”