According to a press release from the Winnipeg Police Department, two individuals were caught after breaking and entering an abandoned house on October 30—after accidentally knocking themselves out. The duo was reportedly in the process of stealing the building’s furnace, but in doing so, they spurred a natural gas leak, which caused them to fall unconscious at the scene.

Natural gas is used to provide hot water and heat in many homes, and it is also required for the use of some appliances. However, it can be dangerous if not properly controlled.

On its own, natural gas is odorless, explains Healthline, which means that gas leaks alone are undetectable to humans—and thus very dangerous. Gas and utility companies add mercaptan (a harmless but awful-smelling compound) to the natural gas supply, giving it that distinctly sulfuric, rotten-egg odor. The smell provides people with an olfactory warning, should there be a leak.

Exposure to natural gas can cause headaches, dizziness, nausea, fatigue, irritation of the eyes and throat, suffocation, and breathing issues. At higher levels, natural gas exposure can cause people to fall unconscious—and even die.

Natural gas is also highly flammable, and a buildup of it in one’s home increases the risk of an explosion or fire.

Winnipeg police arrived at the scene about 5:30 PM Saturday, following reports of a break-in at an abandoned residence by two unknown suspects. According to the police press release, neighbors reportedly began smelling the odor of natural gas emanating from the home, as did police upon their arrival.

From outside, authorities were able to spot the two suspects—but they appeared unconscious. Officers rushed into the building, retrieved the two individuals, and took them back outside. Soon, the suspects regained consciousness and were examined by the Winnipeg Fire Paramedic Service.

Police believe that a gas feed became dislodged as the suspects attempted to take the furnace. This, in turn, caused the natural gas leak, and the two fell unconscious.

The suspects, a man and a woman, are in their 40s. They were detained but soon released without charges, said police.

Global News Canada spoke with Sgt. Dani McKinnon of the Winnipeg Police, who described the situation: “Without any consideration for their own safety, as there is a lot of gas emanating, [officers] rush in and they drag the two people out of the residence,” she said.

“They made a snap decision,” added McKinnon.

However, it remains unknown why the pair was on the hunt for a furnace in particular. “We don’t have an answer to that specific question,” explained the officer to Global News. “I don’t know if they wanted to take it [to] another location, I’m not sure what their goal was.”