This is an archived article and the information in the article may be outdated. Please look at the time stamp on the story to see when it was last updated.

Actor Alec Baldwin fired a prop gun on the set of a Western and killed cinematographer Halyna Hutchins in what he called a “tragic accident.” The director of the movie, Joel Souza, was also injured.

A spokesperson for Baldwin said a prop gun with blanks misfired, and a spokesman for the Santa Fe County sheriff said detectives are investigating exactly what projectile was discharged and how.

The incident has left the internet abuzz with questions — chief among them: How does a prop gun cause a real death?

Prop guns normally fire blanks, which are gunpowder charges that produce light and sound but don’t fire a hard projectile.

In an article for the American Society of Cinematographers, firearms instructor Dave Brown described blanks as being “a cartridge that’s fired from a real or blank-firing firearm.”

“The blank contains no bullet — the actual projectile part of a cartridge — but is loaded with enough gunpowder to create a bright flash at the end of the barrel, thereby convincing the audience that the gun has been fired,” Brown wrote.

Still, blanks can be lethal at close range.

“Even without a projectile, the burning flame, hot gases, and debris from burned and unburned flakes of gunpowder create a very real hazard at close distances,” Brown wrote.

“There’s no reason to have guns loaded with blanks or anything on set anymore,” actor and director Craig Zobel, who worked on HBO’s hit drama “Mare of Easttown,” wrote on Twitter. “It’s an unnecessary risk.”

On-set accidents involving prop weapons have happened before. In 1984, actor Jon-Erik Hexum died after shooting himself in the head with a blank while pretending to play Russian roulette. The gun wasn’t loaded with live ammunition, but the blast was enough to cause fatal head trauma at close range.

In another on-set accident in 1993, the actor Brandon Lee, son of Bruce Lee, was killed after a bullet was left in a prop gun, and similar shootings have occurred involving stage weapons that were accidentally loaded with live rounds.

Gun-safety protocol on sets in the United States has improved since then, said Steven Hall, a veteran director of photography in Britain. But he said one of the riskiest positions to be in is behind the camera because that person is in the line of fire in scenes in which an actor appears to point a gun at the audience.

It was not clear if Baldwin was performing or firing toward a camera at the time of the shooting or how many rounds were fired, and little was known about the weapon.

“There are no words to convey my shock and sadness regarding the tragic accident that took the life of Halyna Hutchins, a wife, mother and deeply admired colleague of ours. I’m fully cooperating with the police investigation,” he wrote on Twitter. “My heart is broken for her husband, their son, and all who knew and loved Halyna.”