The U.S. Justice Department has filed 18 criminal charges against two shipping companies and a senior manager over the 2024 collapse of Baltimore’s Francis Scott Key Bridge, which killed six construction workers.

Prosecutors allege the operators of the cargo ship Dali failed to properly handle repeated power failures and then obstructed investigations and made false statements after the crash.

The ship struck the bridge after losing propulsion, sending debris and pollutants into the Patapsco River and shutting down the Baltimore port for months.

The defendants deny wrongdoing, calling the case an attempt to criminalize a tragic accident and vowing to fight the charges in court, NBC News has reported.

The disaster, described by officials as preventable, caused major economic damage and remains under ongoing legal and civil proceedings.