On-set prop gun supervisor walks through safety procedures, industry standards

The producers of the movie "Rust" told crew members Monday that they were pausing production. At the same time, the investigation continues into last week's prop gun shooting that left cinematographer Halyna Hutchins dead and director Joel Souza hospitalized.

Many questions still remain after a prop gun held by Alec Baldwin was discharged on Oct. 21. Since then, crew members across Hollywood have called for a renewed focus on safety conditions on set.

Armorer Larry Zanoff has supervised the use of guns and ammunition in movies and TV productions for more than 20 years. He said that the industry standards for handling firearms and blank ammunition are actually very stringent.

"The prop master and or the armorer are the people that are responsible on set for firearms, and they would have a chain of custody the entire time that the firearms are outside of any kind of lock up box or safe," Zanoff said.

Zanoff said the first assistant director is the most important safety person on set. They are the ones to dictate when to bring the guns on set and whether the gun will be a "cold gun" or a "hot gun."

"A cold gun would be totally unloaded, nothing in it," said Zanoff. "A hot gun would be one loaded with a blank and ready to do gunfire. The guns should not get loaded until the first [assistant director] directs the armorer to load the specific gun."

On the set of "Rust," records indicated that the assistant director, Dave Halls, was allegedly the one who handed Baldwin the gun and incorrectly advised that the gun was a "cold gun," loaded without any live rounds, according to a search warrant from Santa Fe County obtained by ABC News.

Zanoff said live ammunition is not allowed on a television or film set, instead, blanks are used.

"There's nothing to go flying out of the gun and go down range. What a blank does is simulate gunfire. There will be smoke. There will be a muzzle flash. There will be an audible bang sound to it, in order to simulate the gunfire," Zanoff said. "But there is no projectile in a blank that can go flying downrange."

As the investigation continues, it remains unclear what part of the discharge killed Hutchins, but some have already called for an end to the use of live guns on set.

Zanoff said that he believes that prop-guns are not the problem and that individuals need to adhere to the safety guidelines already in place.

"The use of firearms with blanks has been with us since the beginning of the industry … Millions of rounds have been expended over these different projects, and it's all done safely because they followed the industry guidelines," Zanoff said.

"Obviously, something went terribly wrong in this particular incident. It needs to be investigated. Law enforcement is investigating right now and when they come out with their determination of exactly what happened," he added. "I'm fairly confident that we'll see that the actual industry guidelines were not being followed."