(Mesa County, CA) — A fourth firefighter has succumbed to his injuries sustained from battling a wildfire near the Utah-Colorado border last month. According to officials Nathan Matthews passed away on Friday at the age of 43. He was injured while responding to the Knowles Fire on June 27th and had been receiving treatment for his burn injuries. Emily Barker, Nick Hutcherson, and Sydney Watson were the other firefighters that were killed in that fire as well.