OSHA Bloodborne Pathogens Regulations (Standards) apply to tattoo and piercing.

"The scope and application of the Bloodborne Pathogen Standard is dependent on reasonably anticipated occupational exposure to blood and other potentially infectious materials (OPIM).  Since tattooing and piercing generate blood, workers in this industry would fall under the scope of the standard."
Standard Interpretations 07/29/2002 - Applicability of the Bloodborne Pathogens standard to the tattoo and body piercing industries. OSHA

"The scope of the regulation should not be based on employment in one or a few specified industries....Healthcare workers may therefore be most commonly at risk, but it is their blood exposure, not the industry in which they are exposed, that places them at risk. Regardless of the industry in which they may be exposed, all workers with reasonably anticipated occupational exposure to blood or OPIM should be included in the scope of this rule.
(CDC/NIOSH, Ex 20-634, p.3)" Section 9 -IX Summary and Explanation of the Standard p.2