Passage: Tattooing is associated with two to threefold increased risk of hepatitis C. This can be due to either improperly sterilized equipment or contamination of the dyes being used. Tattoos or piercings performed either before the mid-1980s, "underground," or nonprofessionally are of particular concern, since sterile techniques in such settings may be lacking. The risk also appears to be greater for larger tattoos. It is estimated that nearly half of prison inmates share unsterilized tattooing equipment. It is rare for tattoos in a licensed facility to be directly associated with HCV infection.

Question: Why do prison tattoos have a high risk of infection with HCV?
inmates share unsterilized tattooing equipment