A chemical leak at the PEMEX oil refinery in Deer Park, Texas, released hydrogen sulfide, killing two workers and injuring several others on Thursday.

The leak triggered temporary shelter-in-place orders for residents, but those were lifted after air monitoring showed no hazardous chemicals in the community.

The leak occurred around 4:20 p.m., halting refinery operations. Officials confirmed that no harmful gas escaped beyond the plant despite the lingering odor, CNN has reported.

The sheriff’s office is investigating the incident, and hazmat teams are working to reduce chemical levels inside the facility.

Written by B.C. Begley