Energy safety bureau inspectors interviewing witnesses on Black Elk platform

Offshore oil and gas regulators are investigating what went wrong on board one of Black Elk Energy’s production platforms in the Gulf of Mexico when it exploded on Friday, seriously injuring four workers, killing another and leaving one more missing.

Investigators with the Bureau of Safety and Environmental Enforcement were on the platform today, continuing an inspection that began early Friday, not long after fire was ignited on the shallow-water platform about 18 miles off Louisiana’s coast.

In addition to collecting and safeguarding physical evidence that could shed light on what happened, BSEE investigators were interviewing workers who were on board the facility at the time of the explosion.

According to the agency, the bureau is also ensuring Black Elk makes the platform safe for people to be on board and is overseeing the clean up of residual oil on the site that could spill into the Gulf of Mexico amid rain or sea spray.

In a statement issued late Monday, BSEE Director James Watson said his agency aims for a fulsome investigation.

“BSEE personnel have been working around the clock inspecting the facility, meeting with witnesses and reviewing all available technical documents to ensure that we are able to obtain an accurate representation of what happened on West Delta 32 early Friday morning,” Watson said. “When all of the information is collected and analyzed, BSEE will be in a position to decide which enforcement actions are appropriate and more importantly, how BSEE and the offshore industry can learn from this tragic event in order to prevent loss of life and injuries from future accidents.”

The safety bureau isn’t the only entity probing the lethal fire. Although the Chemical Safety Board hasn’t formally opened an inquiry into the explosion, the agency on Monday subpoenaed documents and information about the accident that could be fodder for a future investigation.

Safety bureau inquiries can span months and can trigger penalties ranging from suspended work to fines. After the Deepwater Horizon disaster in 2010 that killed 11 workers and triggered the nation’s biggest oil spill, the agency issued so-called “incidents of non-compliance” — for violations of offshore drilling rules — to BP, Transocean and Halliburton in connection with that incident.

As a result of BSEE investigations, companies can be forced to suspend operations, their leases can be canceled and they can face fines of up to $40,000 per incident per day.

Since the 2010 Gulf of Mexico oil spill, some lawmakers and regulators have argued that the fines need to be multiplied many times over and that companies with repeated violations should be barred from buying offshore drilling leases or working on the outer continental shelf altogether. Any big fine increase would be up to Congress; current law only allows the safety bureau to make periodic adjustments for cost of living.

Federal regulators have investigated incidents at other Black Elk facilities in the Gulf. For instance, in August, there was a crane accident at one of the company’s facilities. In February 2011, a fire was ignited on a Black Elk platform and later traced to an improperly enclosed rechargeable battery.