Chalmette — State officials are still trying to determine which one of three St. Bernard Parish refineries was responsible for reports of chemical odors in Terrytown on Thursday night, after officials confirmed that sulfur dioxide had been released.

Rodney Mallett, a spokesman for the state Department of Environmental Quality, said officials are examining reams of paperwork to try to figure out if the sulfur dioxide released from Chalmette Refinery LLC, Rain CII Carbon LLC and Valero Refinery exceeded the amounts allowed by their permits. Mallett said all three companies are allowed to release sulfur dioxide at a certain level.

He said state officials conducted air quality tests at the sites Thursday night and found no evidence of an excessive sulfur dioxide release. However, he noted that any release of the chemical can cause people distress because of its strong odor. The state is currently reviewing documentation from meters and gauges at the facilities to try to determine if a problem occurred, Mallett said.

“We cannot pinpoint exactly where it came from,” Mallett noted, adding that reducing sulfur dioxide emissions in general is a state priority. “There’s a lot of variables that go into this. … There’s not just a gauge you can read like at a gas station and tell how much gas you pumped.”

Reports of odors began coming in to the Terrytown Volunteer Fire Department sometime between 8 p.m. and 9 p.m., according to an emergency alert from the parish. Residents reported a strong chemical odor that was causing burning eyes and throats, along with breathing difficulties. Officials believed the odors were coming from St. Bernard Parish, and possibly the Rain CII facility. Terrytown Fire Chief Bryan Adams said his agency actually only received two complaints from residents.

“It wasn’t a big issue for us,” Adams said.

St. Bernard Fire Department Deputy Chief Glenn Ellis said his agency didn’t begin receiving calls until after the Terrytown calls came in. Most of those calls came from people looking for information about a possible release, not reporting any odor themselves.

Ellis noted that the parish has ongoing issues with odors from the Rain CII facility and Chalmette Refinery, but it’s often difficult to figure out which one is causing the problem. Residents can’t identify exactly what they smell, and the companies often point the finger at each other, Ellis said.

“It’s hard to differentiate what they are,” Ellis said about the smells. “They kind of put it off like ‘We’re not having a problem, check with them.’ ”

According to state records, both Rain CII and the Chalmette refinery were the source of odor complaints in 2012. The Chalmette refinery reported an unintentional release of sulfur dioxide on Nov. 18, although no adverse effects were reported at that time. Mallet said that the releases are a problem, and he encouraged any residents who feel ill to seek out medical attention.