New Mexico authorities say an unknown hazardous materials release has sickened about 200 people near the Mexican border just northwest of El Paso, Texas

A mandatory evacuation is under way for two miles around the industrial park and border crossing at Santa Teresa, and the nearby airport is closed. A shelter is open at the local high school.

Officials say 200 people are being treated for light-headedness, nausea and dizziness, but no serious injuries have been reported, and no one has been sent to the hospital.

A system has been activated to alert people in nearby homes and businesses to stay indoors, seal all doors and windows and turn off air conditioning and heating systems.

Air-quality testing is being done to determine what’s making people sick.