BUFFALO, N.Y. (AP) - Authorities are asking why a Buffalo veterans hospital may have reused insulin pens on many patients, causing an HIV scare, despite federal advice to the contrary. Members of the region's congressional delegation are responding to reports that more than 700 patients treated by the Veterans Affairs Western New York Healthcare System may have been exposed to HIV, hepatitis B and hepatitis C between 2010 and 2012. The hospital says that while needles were changed, multi-dose pens intended for single patients may have been used on more than one patient. The Centers for Disease Control and Food and Drug Administration have warned against the practice in recent years, saying there can be a back flow of blood into the pens that can be transmitted to the next user.