The makers of Rust showed "plain indifference to recognised hazards associated with use of firearms on set", according to the New Mexico Environment Department.
The agency has issued the maximum $US136,793 fine to Rust Movie Productions.
Halyna Hutchins was killed and director Joel Souza injured in October as Baldwin rehearsed with what he believed to be a safe gun.
The actor, who was also a producer on the film, has previously said he did not pull the trigger and has no idea how a live bullet came to be on the set.
New Mexico Environment Department cabinet secretary James Kenney said: "There were several management failures and more than sufficient evidence to suggest that if standard industry practices were followed, the fatal shooting of Halyna Hutchins and the serious injury to Joel Sousa would not have occurred.
"Through our investigation, we determined that Rust Productions' failures were both serious and wilful."
He added: "The bottom line here is that it was the employers' obligation to follow national standards, and that did not happen on the set of Rust.
"While this concludes our investigation into this matter, I understand law enforcement is continuing its criminal investigation.
"This was a terrible tragedy and our thoughts are with the victim - a mother, a wife, an experienced cinematographer and a well respected member of the film community. Today we continue to extend our thoughts and prayers to her loved ones.
"While I realise no fine can compensate for the loss of life, we are holding Rust Productions fully accountable."
Photo: AFP Caption Alec Baldwin previously said he did not pull the trigger and has no idea how a live bullet came to be on the set