A new list of known or suspected carcinogens has been released by the National Institute of Environmental Health Sciences (NIEHS), and although most are compounds used in industry, some substances are practically unavoidable by most people.
For example, the Tenth Report on Carcinogens includes broad spectrum ultraviolet radiationwhich is found in sunlightas one of five newly listed "known" carcinogens, because of its strong association with skin cancer and melanoma.
And the use of sunscreen to protect against sunburn may pose its own risk; methyleugenol, a chemical that has been used in sunscreen, as well as in insect attractants and anesthetics, is one of 12 substances listed in the same report as "reasonably suspected to be a human carcinogen." Methyleugenol is also hard to avoidit occurs naturally in oils, herbs and spices and is used in synthetic flavors.
"Methyleugenol has been shown to cause liver and stomach tumors in rats and mice, and thus deserves this listing and further study," said Christopher Portier, director of NIEHS Environmental Toxicology Program, part of the National Toxicology Program (NTP), which produces the list. "While it is in everything we eat, its use has risen dramatically over the last 20 years, especially as an additive to packaged foods."
Other common chemicals on the new list include IQ, the substance produced when various meats and fish are grilled at high temperatures; and steroidal estrogens used in estrogen replacement therapy and birth control pills (see News, Jan. 15, p. 100).
No Need to Panic
But that does not mean that the public, often exposed to these compounds, should panic, or that the substances listed should be banned, Portier said. The biennial report is mandated by Congress as a way for the government to help keep the public informed about substances that most federal agencies already know about and often regulate, especially in industrial settings.
Eight federal regulatory agencies work with a team of NIEHS scientists in a laborious process that can take up to 3 years, but the work does not incorporate an assessment of magnitude of the carcinogenic risk, nor does it establish that any such substance presents a risk to people in their daily lives, Portier said.
"Our purpose is to raise public awareness of hazardous compounds and make it as widely known as possible," he said.
For example, Fred Castrow, II, M.D., said he hopes the word spreads that UV radiation made the list both as a known and suspected carcinogen. Castrow, president of the American Academy of Dermatology, plans to use that fact in his ongoing public relations campaign directed against tanning beds. "I am happy the NIH is lending credibility to our campaign," Castrow said.
Castrow has been trying, fruitlessly, to get the U.S. Food and Drug Administration to ban tanning parlors. "Studies time and time again have shown that overexposure to ultraviolet radiation can lead to skin cancer. There is no safe tanning," he said. "This new listing as a carcinogen should be a wake-up call to people who continue to tan, through natural or artificial sources, despite our repeated warnings."
Impact at State Level
But the question remains as to what impact this latest report will have, besides its value at producing headlines. Formal risk assessments are the responsibility of federal, state, and local health regulatory agencies, and many agencies, such as the Occupational Health and Safety Administration, already have regulations for use of the substances on the books.
"The documents biggest impact is at the state and local levelthats where most regulation falls," said the NTPs Bill Jameson, Ph.D., who has overseen publication of the report for years. He said that some states like California have laws that require substances identified in an authoritative source, like this report, to be regulated as carcinogens, but he is not aware that this practice is widespread.
Still, Jameson said he can cite hundreds of examples of how people have changed their lives because of the reports findings. For example, he told this reporter about a conversation with the head of safety for a large urban school system who had just called about the new listing on wood dust. Now, students in the wood shops of that school district may be required to use respirators and masks. "Knowing a substance causes cancer does produce some changes in behavior," Jameson said.
With publication of the new list, the total number of substances listed as known or suspected carcinogens now stands at 228.
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