A safety supervisor with a BP contractor said the company never warned him or others that a unit that had been down for routine maintenance at the Texas City, Texas, complex was about to come back on line, the Galveston County Daily News reports.

That unit exploded March 23, killing 15 people and injuring more than 100.

Charles Ramirez joined contractor J.E. Merritt in November. He had been a safety representative for the contractor while the company oversaw and staffed the turnaround for BP’s gasoline-producing unit ultracracker, which is located adjacent to the isomerization unit at the center of the fatal explosion.

Ramirez had attended a luncheon hosted by BP to recognize the crew’s safety record while handling the turnaround. He was en route for another meeting when the blast occurred.

The blast killed Ramirez’s supervisor and 14 others, most whose bodies were found in the rubble of the company's trailers, which were used for offices.

Ramirez faulted BP’s lack of communication about the startup of the octane-boosting unit as a reason many were killed and more injured.

“Anybody in the petrochemical business will tell you a startup or shutdown is the most dangerous time,” he told the Daily News.

Ramirez offered an insider's look at the safety culture inside the refinery. He was critical of refinery employees who “did basically what they wanted to,” and noted that safety requirements by his company were far more strict than those of their BP counterparts.

“(It) was just small things, but you learn in safety that if you control all the smaller issues, the larger ones won’t come forth,” he said. “After so many small instances, you are fixing to have a big one,” he told the Daily News.