DENVER -- A man skeet shooting with a group in Weld County was hit by lightning Monday afternoon, knocking him unconscious to the ground and causing his gun to explode in his hands.

Sheriff's deputies said Josh Renuch was with a group of seven people skeet shooting near Highway 392 and County Road 43.

"Apparently, a skeet had just been launched, and the lightning may have hit the shotgun because it pretty much exploded in (Renuch's) hands," said Margie Martinez, of the Weld County Sheriff's Office.

Renuch was hit at about 2:12 p.m., she said.

Robert Muirhead was with the group and heard the lightning strike.

"I decided to go into the house and we heard a big boom," Muirhead said. "Josh got directly hit by lightning and we managed to keep him alive and mostly out of shock and bring him back around."

"(Lightning) can stop someone's heart," said Dr. Tim Hutchison, medical director of North Colorado Medical Center. "It can really cause them to quit breathing. That is why it is so important for people to administer CPR if someone is unresponsive and not breathing."

Renuch was taken to the hospital with first-degree burns on his arms and hands, Martinez said. He remains in critical condition at North Colorado Medical Center.

Brent Kuene was also hit by lightning, but was not seriously injured, Martinez said. He was taken to the hospital as a precaution.

Both victims are in their 30s.

"Brent is doing OK," Muirhead said.

"Where the lightning hit the person, you can have burns there and burns along the path that it takes through the body and the exit wounds as well," said Hutchison. "You can also have ruptured ear drums."

A third person was knocked to the ground during the strike and was treated at the scene. A witness said he tried to stabilize the victim.

Medical professionals and meteorologists said if you hear or see lightning, take shelter.

"If from flash to thunder is 30 seconds or less, you're in the danger zone," said Dr. Richard Ortner, 7News Meteorologist.

"Probably the safest rule is, if you hear it, fear it. If you see it, flee it," said Hutchison.