“Nothing is 100-percent safe,” said Dr. Jeff Duchin, chief of Communicable Disease Epidemiology & Immunization for Seattle & King County Public Health. “You can choose a tattoo parlor and environment where the risk of infection is as low as possible, but it’s never going to be zero.”
One reason for that is the tattoo ink itself, which contains live organisms and has no safety regulations over its production. The FDA has not approved any tattoo inks, and there is no industry standard for water used to dilute ink.
Source: http://goo.gl/YBRUf