The former project manager of a munitions storage and disposal company was sentenced Monday to probation and a fine of $250 for improperly storing explosive material.

An explosion at the Donaldson Enterprises bunker in Waikele on April 8, 2011, killed five people.

“For the past six years this has weighed heavily on my mind,” Carlton Finley told U.S. District Senior Judge Susan Oki Mollway before sentencing.

He named all five victims of the explosion — Bryan Cabalce, Robert Kevin Freeman, Justin Joseph Kelii, Robert Leahey and Neil Benjamin Sprankle — and said he thinks about them every day and offered their families condolences.

The men were in a former Navy munitions bunker dismantling seized illegal aerial fireworks when some of the fireworks ignited.

Finley, an explosive ordnance disposal specialist, also told Mollway in a letter that the explosion and deaths had so shaken him that he is now attending college in the hope of getting a job as an occupational safety and health administration compliance officer.

Investigators deemed the explosion an accident.

Prosecutors, however, later charged Finley, 70, company Director of Operations Charles Donaldson and the company with felony crimes for having the five employees dismantle and treat fireworks without a state permit. Donaldson Enterprises had been subcontracted to store the fireworks, then dispose of them after they were no longer needed for the criminal prosecutions of the people accused of importing them.

In April, a month before the trial, Finley pleaded guilty to a misdemeanor charge in a deal with the prosecutor.

Donaldson and the company went to trial in May. A jury found them not guilty.