A woman is dead, another seriously injured after an explosion Friday morning in a hyperbaric chamber at an equine rehabilitation facility.

28-year-old Erica Marshall was killed, 33-year-old Sorcha Moneley remains in critical condition.

The Kesmarc Rehab Center was one of two places in the area that use equine hyperbaric chambers to treat horses.

"It's like a big white stall for the horse, most of the time, they just stand there," said Brenda McDuffee, general manager at The Sanctuary, where a hyperbaric chamber is used everyday, for one-hour treatments.

"The floors are rubber, they're plastic over rubber, the walls are plastic the floors are grounded, the chamber is grounded," she said.

According to reports, the horse in Friday's accident had not been tranquilized.

However, McDuffee says that's not unusual.

"Some horses are sedated, but that's not a requirement for the chamber-it just depends on that individual animal," she said.

McDuffee says it's a freak accident that's rocked the horse community, however she still believes in the benefits of hyperbaric treatments.

"Certainly its going to make everybody even that much more aware of safety issues, but as far as changing anything, no, we're not going to do more, because we already do everything we can," she said.