HINTON, Iowa (AP) — Authorities have identified two men who were injured in a northwest Iowa grain elevator explosion.

Officials with the Iowa Department of Public Safety announced Monday that 28-year-old Shane Noreen and 24-year-old Gustavo Gutierrez were seriously injured in a Thursday explosion at Central Valley Ag in Hinton.

Both men were transported to an Omaha hospital. An official with Nebraska Medical Center said Noreen was in critical condition and Gutierrez was in fair condition as of Monday afternoon.

Officials with Central Valley Ag did not confirm whether the two men were company employees.

The cause of the explosion hasn’t been determined. The State Fire Marshal Division is assisting the Hinton Fire Department with the investigation.