A union trying to organize Delta Air Lines ground workers, the International Association of Machinists (IAM), called on Delta and authorities to investigate a reported tire explosion at Atlanta’s Hartsfield–Jackson International Airport that killed two Delta employees and injured one.

“As a union committed to the well-being and safety of our members and the broader community, we will offer our resources to anyone affected by this tragic event. We stand with Delta workers during this difficult time and call on Delta and the appropriate authorities to quickly launch a thorough investigation to determine how this happened,” IAM said in a statement.

The IAM represents 100,000 airline workers across North America — but while most U.S. airlines are heavily unionized, Delta is not. The IAM is pushing to unionize Delta’s ramp workers, tower workers and baggage handlers, while the Teamsters union is pushing to unionize its mechanics.

Just last month, IAM organizers held a small rally with Delta workers near the airport in support of unionization.

In a post on X, Atlanta Mayor Andre Dickens expressed his “deepest condolences” to the families and loved ones of the deceased and expressed his thoughts to those injured. The mayor said police, firefighters and airport officials were on site.

John Laughter, Chief of Operations at Delta TechOps, said in a memo to TechOps employees that Atlanta Civic Circle that he is “deeply saddened to report that three TechOps team members were involved in an accident that occurred early this morning at Atlanta TOC 3, Dept. 391 – Wheel & Brake Shop. Tragically, two of our team members involved have died and another team member was seriously injured.”

“We extend our full support to their families during this difficult time and are conducting an investigation to find out what happened,” Laughter’s memo said.

A Delta spokesman said in a statement: “We are now working with local authorities and conducting a full investigation to find out what happened.”