Water contamination has some Duncan residents resorting to bottled water.
Halliburton Company said it found contamination in 18 water wells in Duncan. The company is now taking steps to correct the problem.
Halliburton said it detected a colorless salt, that could in high enough concentration, cause adverse health effects.
The company said the wells are located on Duncan's north side, where Halliburton used to perform government contract work involving removing and burning missile fuel.
It's been 20 years since Halliburton conducted operations at the site but the company thinks the work probably contributed to the groundwater contamination.