More and more people are getting tattoos these days- thanks to the trend set by celebrities like singers the late Amy Winehouse and Christina Aguilera, actors Angelina Jolie and Jake Gyllenhaal, and soccer star David Beckham. However, recent studies have found that the inks contain a host of dodgy substances, including some phthalates, metals, and hydrocarbons that are carcinogens and endocrine disruptors, prompting the U.S. Food and Drug Administration to launch a probe. One chemical commonly used to make black tattoo ink called benzo(a)pyrene is known to be a potent carcinogen that causes skin cancer in animal tests, reports the Daily Mail . According to scientists, coloured inks often contain lead, cadmium, chromium, nickel, titanium and other heavy metals that could trigger allergies or diseases. Some pigments are industrial grade dyes "suitable for printers' ink or automobile paint," says an FDA fact sheet. The FDA has launched an investigation into the long-term safety of the inks, including what happens when they break down in the body or fade from light exposure. "The short answer is we don't know if the chemicals in tattoo inks represent a health hazard," Joseph Braun, an environmental epidemiologist at Harvard University in Boston, Massachusetts, told Environmental Health News .