CHARLES TOWN, W.Va. -- At least two hunters have died and three others were injured today on the opening day of West Virginia’s gun season for bucks.

All but one of the deaths is due to suspected carbon monoxide poisoning.

A 37-year-old man from San Antonio died today after being overcome by carbon monoxide from a lantern inside a trailer he and another hunter were using.

Wetzel County Sheriff James Hoskins said the man’s 38-year-old hunting partner from Pennsylvania was flown to Allegheny General Hospital in Pittsburgh.

The two men, whose names were being withheld, were hunting in the area of Four Mile near Pine Grove, W.Va.

The Putnam County Sheriff’s Department says three hunters were being treated for carbon monoxide poisoning after being overcome by fumes inside a camper.

In Marshall County, an unidentified hunter died in the woods.

His death is believed to be natural causes.