Authorities tell The Buffalo News that there's a "very small risk" for the diabetic patients who may have been exposed to the reused insulin pens between October 2010 and November 2012.
The VA memo obtained by the News says the problem was revealed by a routine pharmacy inspection.
A hospital spokeswoman says the needles were always changed, but an insulin pen may have been used on more than one patient.
The VA is offering free blood tests to rule out any infections.
(Copyright 2013 by The Associated Press. All Rights Reserved.)