Earlier this month, we reported that two weeks before BP’s blowout in the Gulf of Mexico, the company’s refinery in Texas City, Texas, released 538,000 pounds of toxic chemicals into the air. The release, as we noted, went on for 40 days as the company tried to repair a key piece of equipment without stopping production.

According to The Daily News of Galveston, Texas, the state attorney general’s office is now investigating the release and looking closely at whether BP satisfied all reporting requirements.

The case is serious enough that the Texas Commission on Environmental Quality referred the issue directly to the state attorney general, commission spokeswoman Andrea Morrow told the Daily News. This is not standard practice:

Normally, the environmental agency would file an enforcement citation called an agreed order that would outline the company’s violations, associated fines and orders on what processes or equipment needed corrective action. Only if the company disagreed with the TCEQ findings would the case be sent to the attorney general.

Because of the seriousness of the event and a pending attorney general’s lawsuit against BP for environmental violations, the case instead was filed directly with the attorney general Tuesday, Morrow said.

Last year, the Texas attorney general filed a civil suit against BP for “poor operating and maintenance practices” that resulted in 53 separate incidents of excessive emissions. The Texas City refinery is most infamous for a 2005 explosion that killed 15 people, but as we’ve reported, “four more workers have died in various accidents since then, and two chemical releases in 2007 sent more than 130 people to the hospital.”

Continued violations at the refinery—including failure to repair some of the very problems that led to the 2005 blast—prompted the Occupational Safety and Health Administration to fine BP a record $87 million last year. That fine remains unpaid.

If the Texas attorney general finds grounds for another lawsuit over the 40-day toxic release, the charges would be not be rolled into the current litigation, but would be treated instead as a separate case, the Daily News reported.

BP spokesman Michael Marr wouldn’t comment on the litigation to the Daily News, but said, “We have implemented substantial enhancement in safety and environmental performance and reporting of emissions events at the Texas City refinery.”