Authorities in Windsor, Ontario are investigating an explosion at a Stellantis factory that they believe was an intentional act.

The explosion occurred on Thursday evening in a storage area. A explosive disposal unit located a “suspicious package” that had been detonated while investigating the explosion. No one was injured and the explosion didn’t trigger a fire.

“Through investigation, EDU [Explosive Disposal Unit] located a suspicious package that detonated. Further examination and testing of the package will occur as part of the investigation,” the Windsor Police Service said in a statement. “It should be noted that the suspicious device was located in the area of the facility not generally used for general work and acts as a storage facility. The incident occurred on the west side of the facility on the second floor. Investigators do believe this was an intentional act and are seeking any information that may help identify a suspect of suspects.”

Read Also: Stellantis’ Warren Truck Plant Hit With Air Quality Violation

A spokesperson from Stellantis confirmed that the plant was evacuated after the explosion before workers returned to work later that evening.

“Over the last couple of weeks, there have been some incidents going on in the plant-based on anxieties,” local union president Dave Cassidy said in a Facebook post sent to members of Unifor Local 444. “I know we have had some hard news as of late, but any lashing out in the facilities cannot and will not be accepted and needs to stop. All our livelihoods depend on the future of the plant. Trust and know that we are working through the unprecedented challenges that we are up against right now. Our priorities will always be the safety of our members and their long-term future employment. Any antics will negatively affect our reputation and our future, that is a fact.”

Speaking with The Detroit Free Press, Cassidy said the Windsor site has only operated for 15 weeks this year due to the semiconductor shortage.