MIDDLETOWN, Conn. (WTNH) — It has been 13 years since six people were killed in a deadly explosion at the Kleen Energy plant in Middletown.

Political leaders and union officials gathered Sunday to honor those who were lost, along with the dozens injured, in the blast. The ceremony included laying a wreath at the permanent memorial outside the Kleen Energy plant.

The explosion claimed the lives of Peter Chepulis, Ronald Crabb, Raymond Dobratz, Kenneth Haskell, Jr., Roy Rushton and Vance Walters.

“This incident has a huge impact on the state, on emergency responders, and they often say that time heals all — but here are 13 years later,” South Fire District Middletown Chief James Trzaski said. “Although time may heal, there are scars that are left behind.”