BATON ROUGE — ExxonMobil's plastics plant in Baton Rouge had an "operational issue" in one of its units Monday, resulting in a loud noise that its neighbors may have heard.

The company said there was no emergency and that safety systems worked appropriately. Air quality was not impacted, it said.

"The unit safety devices were activated, as designed, and relieved pressure on the unit. The relief of the pressure caused a loud noise that may have been heard by surrounding neighbors," ExxonMobil said in a post on its Facebook page.

The company did not say which unit was involved.