I've seen this post quite a few times, usually once a month.
Firstly, I find it hard to believe that gas station attendants wouldn't notice someone affixing hypodermic needles to gas station pumps.
Secondly, it's a hoax that started out as a terror chain email.
When these emails started out originally, it was from a Captain Abraham Sands of the Jacksonville Police Dept in Florida.
There is no Jacksonville Police Department. Jacksonville is served by the Jacksonville Sheriff's Office. There is no Captain Abraham Sands employed by the Jacksonville Sheriff's Office.
A new version of the Capt. Sands/pump needles email is circulating. It is identical to the original except that someone changed all references to Jacksonville, Florida to Buffalo, New York. Needless to say, there is no Capt. Sands in Buffalo or Jacksonville.
Now there are newer versions now stating anybody saying anything but just giving the warning and having the same amount of cases (usually 16 or 17).
On the other hand, urban legends have multitudes of variations. Why? People have faulty memories.
I wish people everywhere would stop sending it along because it isn't true.