For years, the tattoo business has been largely ignored by the F.D.A. Tattoo parlors are regulated by state and local authorities, but the inks used in tattoos are subject to F.D.A. rules for cosmetics and color additives. The F.D.A. admits that it hasn’t been paying much attention to the issue. “Because of other public health priorities and a previous lack of evidence of safety concerns, F.D.A. has not traditionally regulated tattoo inks or the pigments used in them,'’ according to a new report from the agency called “Think Before You Ink.'’

But at a time when tattoos and permanent makeup are surging in popularity, the F.D.A. is now promising stepped up vigilance on tattoo safety. The agency says it has received reports of bad reactions to tattoo inks even years after the procedure is performed. Some people say their tattoos itch or become inflamed in the summer after being in the sun. The F.D.A.’s Arkansas-based National Center for Toxicological Research is now investigating the chemicals used in tattoo inks and how they break down in the body, how the inks interact with light and the short- and long-term safety of pigments used in tattoo inks.

“Our hope is to get a better understanding of the body’s response to tattoos and their impact on human health, and to identify products at greatest risk,” said Dr. Linda Katz, director of the F.D.A.’s Office of Cosmetics and Colors in the Center for Food Safety and Applied Nutrition.

One of the big unknowns about tattoos is what happens to the ink when tattoos are exposed to sunlight and laser lights used in tattoo removal. It’s known that tattoos fade over time. “We want to know what happens to the ink,” said research chemist Paul Howard, one of the tattoo investigators. “Where does the pigment go?”

Some research has shown that pigment migrates from the tattoo site to the body’s lymph nodes. It’s not known whether the presence of tattoo ink in lymph nodes has any health consequences.

Tattoos are made by using a needle that injects colored ink below the skin surface. Permanent makeup is a tattoo that mimics cosmetics, like eye or lip liner. Known risks include contracting hepatitis or H.I.V. from dirty needles, allergic reactions to the ink, scarring and small knots or bumps that form around the tattoo site. Some people with tattoos experience short-term swelling or burning if they later need to undergo a magnetic resonance imaging scan.

Until more is known, the F.D.A. warns consumers that it has not approved any tattoo inks for injection into the skin, and many ink pigments used are industrial strength colors suitable for printers’ ink or automobile paint.

For the full article from the F.D.A., click here. The FDA also offers this Web site, which contains information about the risks of tattoos. And to learn more about erasing tattoos, read this article from Times reporter Natasha Singer.