More than 700 newborns and 40 employees of a Texas hospital may have been exposed to a worker who had an active case of the sometimes-deadly tuberculosis, health officials said on Friday.

The employee, working in a nursery at Providence Memorial Hospital in El Paso, interacted with patients for months before later being diagnosed with the disease, the El Paso Department of Public Health said.

A total of 706 babies and 43 employees were possibly exposed to the infected worker between September 2013 and August 2014, the health department said. Health and hospital officials were working to contact the affected families and would provide screening and follow-up care free of charge.

"TB is a serious but treatable disease that is spread through the air. Although TB is not easy to catch from another person, we want to be extra sure that your child is examined," the health department said in a letter to parents.

Tuberculosis, a potentially fatal disease that generally affects the lungs, can lay dormant in a person's body for months or years and is spread when person with an active case coughs, sneezes, or speaks, according to the U.S. Centers for Disease Control and Prevention.

Babies, and other people with weakened immune systems, are particularly vulnerable to becoming infeced, the CDC said.