SANTA TERESA, N.M. (AP) — An industrial park near the New Mexico-Texas border reopened Wednesday a day after about 200 people were sickened by an unknown substance.

The complex of factories and warehouses in Santa Teresa, N.M., was reopened at 6 a.m. after testing for hazard-ous materials came up empty, Dona Ana County emergency officials said. The Dona Ana County Airport in Santa Teresa also reopened.

Santa Teresa is just northwest of El Paso, Texas.

People in the complex began complaining of difficulty breathing, light-headedness, nausea and dizziness about 8:30 a.m. Tuesday. Some reported a burning sensation on their skin, but no serious injuries were reported.

An investigation initially centered at the FoamEx plant on the industrial park campus but was expanded to other areas in the park.

A 1-mile area surrounding the Dona Ana County Industrial Park and Mexico border crossing at Santa Teresa was evacuated for a few hours and the county airport was closed. Workers a few miles away said they could smell some-thing in the air.

"I got there after they barricaded the road. When I rolled down the window, I started feeling irritation on my skin," said Gerardo Gomez, who was on his way to work. "It felt like when you get chile on your skin."

Officials said some people from businesses in the industrial park were taken to Santa Teresa High School as a precaution.

Classes were cancelled Tuesday at a medical college located in the industrial area, which is also home to wire and paper manufacturing businesses and warehouses.