State and local officials were continuing Thursday to investigate reports of a sulfur-like odor near St. Rose, but they said ongoing air-quality monitoring indicated that the odor does not pose a health hazard to residents.

Crews from the Louisiana Department of Environmental Quality and the St. Charles Parish Emergency Operations Center were investigating the source of the odor, officials said.

DEQ spokesman Greg Langley said investigators think they have narrowed it down to two possible sources: the International-Matex Tank Terminals or a nearby Shell oil refinery.

“We’re not going to stop looking, of course, but right now, we don’t feel it poses a hazard to human health,” Langley said. “There’s nothing in the readings that pose a hazard to human health.”

Officials began investigating the odor Wednesday. They have not recommended the public take any protective measures.

Residents may call the St. Charles Emergency Operations Center at (985) 783-5050 24 hours a day for more information or to make odor reports.