A new case report from France offers a reminder of why people who use medical devices like asthma inhalers should take warnings on the product label seriously.

A 74-year-old asthmatic man was burning leaves when he heard an explosion and felt something pierce the right side of his chest. At the hospital, doctors found an entry wound between his ribs, but no exit wound.

Imaging revealed what appeared to be a nebulizer canister wedged between his liver and diaphragm. Doctors believe the man’s inhaler fell from his pocket into the fire and exploded.

Dr. Stanislas Ledochowski of the Hospitalier Universitaire Lyons Sud, who examined the man, told Reuters Health, “Fortunately, it is to be considered as an exceptional event, and since it was the only described case in the medical literature, we thought describing such an occurrence could be of medical interest.”

Inhalers, a portable form of nebulizer, turn liquid medication into a fine mist, which is the fastest way for people with asthma or other lung conditions to dose themselves during an attack.

But the devices contain pressurized gas along with medication, and canisters of albuterol, the drug the patient used, carry a warning to keep them away from flames or high heat.

The National Institutes of Health also warns that albuterol should be kept out of the reach of children, stored at room temperature and kept in its foil pouch until needed.

Ledochowski and his coauthors describe in the journal Surgery what they found when they went in to remove the foreign object. The burnt canister was lodged between the man’s liver, which suffered no damage, and his diaphragm, which was slightly ruptured.

In some cases of chest trauma, they write, doctors decide that it would be better to leave the foreign object in place. But to avoid the risk of infection, Ledochowski surgically removed the canister.

About 25 million Americans have asthma, and according to the U.S. Centers for Disease Control and Prevention, that number increases every year.

“The general public should understand, that all medical devices and drugs are designed for a specific purpose and that their unreasoned use, voluntary or not, can have severe consequences,” Ledochowski said.

“What was exceptional in this case report is the severity of the sustained trauma and the object responsible for the trauma,” he said. “As with every domestic device that contains gas, the warning about not approaching these objects to a heat source has to be respected.”