The prop gun used by Alec Baldwin in the accidental death of cinematographer Halyna Hutchins and injury of director Joel Souza on the New Mexico set of the Western film, Rust, on Thursday contained a live single round. The news was shared in an email sent by International Alliance of Theatrical Stage Employees (IATSE) Local 44, the parent union that represents most U.S. production workers, to its members, Variety is reporting.

“A live single round was accidentally fired on set by the principal actor, hitting both the Director of Photography, Local 600 member Halyna Hutchins, and Director Joel Souza,” the union’s statement to its members in the email. IATSE Local 44 Secretary-Treasurer Anthony Pawluc also called the event “an accidental weapons discharge” in the statement.

The email also stated that the Santa Fe crew members who were working on the drama’s set handled the props. The movie’s crew members also staffed the set decoration, special effects and construction departments, not IATSE’s union members.

“Local 44 has confirmed that the Props, Set Decoration, Special Effects and Construction Departments were staffed by New Mexico crew members,” Pawluc said. “There were no Local 44 members on the call sheet. On behalf of Local 44’s Officers, Executive Board and Staff, our thoughts and prayers go out to Halyna and her family. We also send good thoughts to Joel and his family for a full recovery.”

IATSE also stated in the email: “Our entire alliance mourns this unspeakable loss with Halyna’s family, friends, and the Rust crew. We are activating our partnerships across the industry to provide support and resources to our sisters, brothers, and kin.”

The email continued by stating: “Creating a culture of safety requires relentless vigilance from every one of us, day in and day out. Please, if you see something, say something. If you feel unsafe on set for any reason, including harassment, send us a tip via the IATSE Safety Hotline at 844-422-9273 or using our safety info app.”

Rust‘s production company initially reported on Thursday afternoon that the incident involved blanks. But the Santa Fe County Sheriff’s office later said in a police report that it was too soon to determine what type of round was used.

The police report also revealed that one of the Western’s assistant directors (AD) permitted Baldwin to use the prop gun that was involved in the incident, The Wrap is reporting. The AD, whose name has not been publicly revealed, picked up a prop pistol from a cart and yelled “Cold gun!” before handing it to the actor.

The AD’s use of the term cold gun indicated that the prop gun didn’t contain any live rounds, including blanks. It was also supposed to be safe to use around nearby crew members.

According to a search warrant affidavit signed by Alliance of Theatrical Stage Employees , the AD was unaware that the prop gun contained live rounds when handing it to Baldwin. The report didn’t state which type of ammunition it held or how many rounds were fired by the actor.

The affidavit also states that Baldwin had been standing behind Hutchins when he discharged the firearm. The shots then hit the cinematographer in the chest and Souza in the shoulder.

The person in charge of prop firearms on Thursday was an armorer named Hannah Gutierrez Reed, according to a call sheet for the film, the reviewed by the Wall Street Journal is reporting. It was her first time being the head armorer on a film set. However, her father was well known in the industry and trained her on firearms and props from a young age.

The accident on Thursday wasn’t the first time a firearm had misfired on Rust‘s set, according to the drama’s crew. Gun inspections and other safety concerns weren’t up to industry standards. The crew members who were on set last Saturday, October 16, have said that Baldwin’s stunt double accidentally fired two rounds despite being told that the gun was cold.

In the hours before Thursday’s fatal shooting, six members of the camera crew left the set in protest. They were concerned about the safety of the production and poor working conditions for the movie, including overlong hours and a lack of staff housing.

They were replaced by non-union members.

“The safety of our cast and crew is the top priority of Rust Productions and everyone associated with the company,” Rust Movie Productions said in a statement following the incidents. “Though we were not made aware of any official complaints concerning weapon or prop safety on set, we will be conducting an internal review of our procedures while production is shut down. We will continue to cooperate with the Santa Fe authorities in their investigation and offer mental health services to the cast and crew during this tragic time.”

After the incident, Hutchins was airlifted by helicopter to the University of New Mexico Hospital in Albuquerque, where died of her injuries. Souza was was taken by ambulance from Rust‘s set on the Bonanza Creek Ranch  to St. Vincent Regional Medical Center in Santa Fe to receive emergency treatment for his injuries. He was released later that day.

The accident is still under investigation by the Santa Fe County Sheriff’s Office. Baldwin has been questioned by law enforcement, but no charges have been made in connection with the shooting.

“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,” Baldwin tweeted yesterday about the incident. “I’m fully cooperating with the police investigation to address how this tragedy occurred and I am in touch with her husband, offering my support to him and his family. My heart is broken for her husband, their son, and all who knew and loved Halyna.

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