Three of the 24 rig workers on a platform operated by Black Elk Energy died in a mid-November accident off the coast of Louisiana.
The company said the incident occurred during a "construction project." Investigators said rig workers cut into a pipeline on the platform that had oil inside, sparking the blaze.
Black Elk said last month a third party investigation found contractors failed to follow basic safety standards.
Tony Scott, general manager of offshore safety company OCS Group, told energy reporting website Rigzone lack of training was a likely factor in the incident.
"If the workers knew more about the dangers around them, the fatalities may well have been avoided," he said in an interview published Wednesday.
Scott said extreme temperatures, not just a spark, could lead to an explosion of vapors.
The Philippine Embassy to the United States confirmed its nationals were among the dead. Ambassador Jose Cuisia said last year the nine Filipinos on the platform at the time of the Nov. 16 incident would not have been there had they had proper training.