A company that billed itself as manufacturing the “safest, most advanced and most reliable chambers in the world” is asking users to stop operating its hyperbaric oxygen chambers following last week’s fatal explosion in Ocala, Fla.

In a letter to customers, Lexington, Ky.-based Veterinary Hyperbaric Oxygen offered “sincere condolences” to those impacted by the Feb. 10 explosion at the Kentucky Equine Sports Medicine & Rehabilitation Center, or KESMARC.

KESMARC employee Erica Marshall, 28, was killed along with a horse inside the chamber that exploded. A female intern working nearby in the center sustained injuries.

In its letter, Veterinary Hyperbaric Oxygen asks users of its chambers to shut down until investigators can pinpoint the cause of the explosion. Local media have reported that a horse inside the hyperbaric oxygen chamber kicked off a protective cover over its shoes.

The two employees monitoring the horse tried to shut down the unit, but that didn’t happen before the horse’s hoof apparently struck the chamber’s side, igniting a spark that caused the explosion, according to Florida-based news reports.

The State Fire Marshal is investigating, and Veterinary Hyperbaric Oxygen notes in its letter that a representative for the company was sent to Florida to assist those efforts. Officials with Marion County Fire Rescue tell the VIN News Service that a report from the State Fire Marshal should come out within the next three weeks.

Until then, it’s impossible to know exactly what happened, said Dennis Geiser, DVM, DABVP-Equine, director of the hyperbaric services at the University of Tennessee’s (UT) Department of Large Animal Clinical Sciences in the veterinary college.

"They need to figure out if there’s anything faulty with the chamber or there was some other cause,” he said. “They’re trying to shut things down and rightly so.”

According to the company’s website, Veterinary Hyperbaric Oxygen is a global distributor of hyperbaric oxygen chambers for horses and companion animals.

Patients receiving hyperbaric oxygen therapy breathe very high concentrations of oxygen while they're placed in a chamber that increases the pressure around them. This pressure elevates the amount of oxygen in a patient's blood by as much as 15 times normal levels. The increased pressure condenses the oxygen molecules making more molecules available for the blood to pick up in the lung.

That description comes from the website of UT, perhaps the only veterinary college in the country doing hyperbaric oxygen therapy. "The goal is to increase the amount of oxygen delivered to the diseased tissue to help it to heal," the website said, offering services for either of UT's two hyperbaric oxygen chambers.

One chamber is designed for small animals and the other is for equine, manufactured by Veterinary Hyperbaric Oxygen. “We’ve been doing hyperbaric therapy for six, going on seven, years,” Geiser explained, noting that he’s never had a problem with the chambers but that they're not used with great frequency.

Dr. Ronald Lyman estimates logging 16,500 sessions in his practice’s hyperbaric oxygen chamber during the past eight years. The owner of Animal Emergency and Referral Center in Fort Pierce, Fla., doesn’t treat horses; dogs and cats make up the majority of patients at his practice.

Rather than using a chamber manufactured specifically for veterinary medicine, he bought one designed for humans that he purchased from a hospital that closed in New York. “It's a totally different thing,” he said, noting that chambers for equine are much larger.

For veterinarians promoting hyperbaric oxygen therapy for companion animals, buying units designed for humans is common practice.

“Hyperbaric oxygen therapy is making its way into veterinary medicine and has been for the past 10 years, especially for companion animals,” Lyman explained. He describes oxygen therapy as a “tremendous clinical tool that’s changed the outcome of so many medical cases,” specifically referring to patients with pancreatitis. He also notes that the therapy is used to treat anemic animals and spinal injuries. Right now, he’s using the oxygen therapy to treat a cat with a skin wound that otherwise is not healing.

Regarding the safety of hyperbaric oxygen chambers, Lyman notes that training and safety is key. “It is oxygen under pressure,” he said. “You have to use caution because you don’t want to get in a position where you’d have combustion.”

He considers the explosion in Florida to be a “wakeup call” for safety.

"It’s certainly a tremendously sad thing,” Lyman said. “The No. 1 priority is safety and training, and that’s true for everything from driving your car to giving a medication.”