The Killeen Educators Association took to social media to notify parents that students may have been exposed to tuberculosis at 4 area schools. The suspected source of the exposure? A substitute teacher.

Word came from The Bell County Health Department that the chance of exposure had occurred at Patterson, Eastern Hills, Mannor, and Union Grove Middle School. While the association reports the risk to be low, students may have been subject to exposure in 50 to 100 minute sessions. State health officials say it usually takes six to eight hours of exposure to cause infection. The school district does not currently preform pre-employment screenings or regular TB tests on it's employees.