An asphalt production facility in St. Rose has been identified as the source of a sulfur-like odor that has plagued residents near St. Rose for almost two weeks, state and parish officials said Friday.

The facility, owned by International-Matex Tank Terminals and Shell Chemical, is being upgraded with a caustic scrubber. Also, the feedstock suspected of having caused the odor is being removed from the plants, and a new cooperative odor control plan will provide odor notification to Shell, IMTT, St. Charles Parish and the Louisiana Department of Environmental Quality, officials said.

The two plants involved, Shell Chemical and International-Matex Tank Terminals, are sharing responsibility for the odor, officials said. No odor complaints have been received by the parish since June 14, they said.

LDEQ continues to monitor the site, and the incident remains under investigation, officials said.

“Shell and IMTT are working collaboratively to immediately install additional odor control equipment to remove trace non-toxic sulfur compounds,” the companies said in a joint statement Friday. “Shell and IMTT are also working jointly on an improved process to notify state and local officials. A release of any kind is something Shell and IMTT take very seriously. The protection of the communities where we operate, our workers, and the environment remain our top priorities.”

Last week, a local environmental watchdog group, the Louisiana Bucket Brigade, said it had received dozens of calls from area residents complaining of feeling sick since the odor appeared.

State and parish officials said last week that ongoing air-quality monitoring indicated the odor did not pose a health hazard to residents.

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.