It all started when that nurse was overheard saying to someone else that it’s okay to reuse the pen on multiple people.
More than 4,000 patients got the unnerving letter from South Nassau Communities Hospital on Long Island warning them about the exposure.
A hospital spokesperson said the risk is low and that they jumped to action as soon as they heard.
"Once that was said, we then followed through with a report to the state Department of Health."
The hospital is now urging patients to get tested for HIV, hepatitis B, and hepatitis C.
This may sound familiar to some. An oral surgery office in Tulsa, Okla. was in a similar situation in 2013 when it was found to have potentially exposed around 7,000 patients to HIV and Hepatitis C.
Only a few cases of transmission were linked back to the offices of Dr. Scott Harrington, who is no longer practicing.
As for the Long Island hospital, it has stopped using the multi-use pens and has gone back to the old method of using single-use insulin vials.