More than 700 babies and 40 health workers have been exposed to tuberculosis in an El Paso, Texas, hospital, the city’s Department of Public Health announced.

At some point between September 2013 and August 2014, a Providence Memorial Hospital employee with TB, as the disease is commonly known, entered the hospital and worked in close proximity with infants, CNN reported Monday.

It is unknown whether any of those exposed have subsequently tested positive for tuberculosis, which can be fatal. The hospital and the health department promised free care for anyone infected and said they have alerted each person at risk by phone call and letter.

“This is one of the largest TB exposure investigations we’ve ever been involved in, and it involves infants, so it is particularly sensitive,” Carrie Williams, the director of media relations for the Texas Department of State Health Services, told CNN. “Babies are more likely than older children and adults to develop life-threatening forms of TB.”

The department investigated last week and reported that the hospital’s infection-management standards were lacking. The Centers for Medicare & Medicaid Services gave the hospital an Oct. 11 deadline to identify changes in protocol to prevent similar exposures in the future — otherwise it will cut off Medicare and Medicaid funding.

Active cases of TB can spread through the air when an infected person coughs and sneezes. Typically treatment requires months of antibiotics, although an infection can stay dormant in patients and not show symptoms, which include breathing difficulties and chest pains.

The employee who was initially infected is no longer working at the hospital but is reportedly receiving treatment.

[CNN]

Write to Nolan Feeney at nolan.feeney@time.com.