A British woman and a horse have been killed in an explosion at an equine facility in Florida.

A hyperbaric – or oxygen – chamber at Kentucky Equine Sports Medicine and Rehabilitation Centre in Marion County exploded, blowing off part of the roof and wall of the chamber, and killing 28-year-old Erica Marshall, who was observing on a video in a nearby room.

The horse inside, six-year-old eventer Landmark’s Legendary Affaire, from Virginia, also died. The horse was in Florida with the O’Connor Event Team. Landmark’s Legendary Affaire had been ridden by Lauren Kieffer and was owned by Jacqueline Mars.

The incident happened on Friday morning (10 February).

The noise was reportedly heard over 30 miles away and debris was thrown over an area covering more than 1,200sqft.

Erica, a graduate of Hartpury College in Glos, had been working for Kesmarc for two years.

She treated between two and six horses a day in the chamber, which is designed to help conditions including tendonitis, colic, sinus infections, laminitis and bleeding.

A hyperbaric chamber is highly pressurised and increases the amount of oxygen in blood by as much as 15-times the normal level.

The horse reportedly kicked out in the chamber and a metal shoe ignited a spark. Erica tried to shut down the equipment but did not have time.

The horse had been in chamber four previous times, without incident.

Sorcha Moneley, from Ireland, was seriously injured in the blast.

In 2008 a horse died in an accident in a hyperbaric chamber in Newmarket.

House Of Wisdom, an unraced Godolphin two-year-old, was in undergoing treatment for a hind suspensory condition when the chamber caught fire.