According to the Department of Veterans Affairs, two people have tested HIV positive after being treated with dirty equipment at the agency’s Miami hospitals, The Associated Press reports. In total, four VA patients have tested positive, with other cases reported in Murfreesboro, Tennessee, and Augusta, Georgia.

The VA is looking into the cleaning procedures of medical equipment used during colonoscopies. Materials used in ear, nose, and throat exams at its Southeast hospitals will be investigated as well.

According to the article, 20 VA patients have also tested positive for hepatitis C. While it is uncertain whether the HIV and hepatitis cases are directly linked to VA treatment, the agency has advised nearly 11,000 veterans treated at its hospitals to get blood tests.