New York Times
4 March 2003

Agency Says Children's Risk Is Higher for Some Cancers
By Jennifer 8. Lee

WASHINGTON, March 3 — After assessing the scientific research, the Environmental Protection Agency said today that when compared with adults, children younger than 2 faced a tenfold risk of developing cancer if they were exposed to some substances.

The substances, known as mutagens and used in some industrial processes, cause cancer by damaging DNA. Because the E.P.A. has long known about the toxicity of certain kinds of mutagens, the agency has moved to ban their use.

The conclusion was part of a draft report that represented the agency's first try at assessing children's risk to cancer-causing agents. The draft will be subject to public comment and scientific peer review.

Environmental health dangers to children have been the center of contentious scientific and policy debate over the last six years, resulting in a push for more development-focused cancer studies. Most cancer research has historically centered on adults, with most of the data collected through occupational exposure and tests on adult animals.

But children ages 2 to 15 have a cancer risk three times that of adults. The E.P.A. says it is waiting for additional research before determining whether children are at increased risk from other carcinogens.

The amount of scientific literature that shaped the children's guidelines was relatively modest. The guidelines are among the government's first formal steps to incorporate recent research into procedures that are used to set environmental standards, something environmental groups have been lobbying for.

"It's a step in the right direction, because kids are clearly more at risk and government is trying to quantitate that and use that in a meaningful way," said Kristina Thayer, a senior scientist with the Environmental Working Group, an advocacy group that has focused on children's environmental health.

The draft guidelines for children, which were released today for comment and review, are part of a broader revision of E.P.A.'s cancer-risk guidelines, first introduced in 1986. Risk assessments are a contentious topic for the agency, which has faced criticism from industries and environmental groups for its estimates.

"There is so much controversy around these risk assessments," said William H. McFarland, the agency's acting deputy administrator for science. " `You're overstating the case. You're understating the case. They are unrealistic. They are clear enough to take action.' "

As scientific understanding and computer modeling become more sophisticated, the E.P.A. is modifying its guidelines to go beyond "one-size-fits-all" analysis. For example, as part of the general assessment, the agency is encouraging a more descriptive approach to characterizing a substance's cancer-causing potential. For example, the report said, scientists should emphasize whether the risk comes through breathing, ingesting or touching a carcinogen. As part of the effort, the agency is looking at sensitive groups, such as children, people with diabetes and the elderly.

Risk assessment has two main components: how a substance hurts the body, and the probability of coming into contact with that substance. In trying to more accurately assess the risks for different groups, the E.P.A. is adopting procedures that incorporate elements of biology and lifestyle.

In the past, cancer risk assessments might have focused only on how a dose of toxic chemical might affect the human body. The newer guidelines encourage the agency's scientists to consider other factors, including that children spend more time outside, that they often put their hands in their mouth, and that they eat, drink and breathe in greater proportion to their body weights than do adults. At the same time, children are less susceptible to occupational cancer risks.

The children's guidelines were issued as a supplement to the overall risk-assessment report, which must be be peer-reviewed by the agency's scientific advisory board. Keeping the children's guidelines separate also makes them "lean, mean and easier to update," said James Coliano, the chairman of the E.P.A. group that writes cancer guidelines.

To be sure, there are many categories of carcinogens, and children are not at increased increased cancer risk from all of them. Because mutagens damage DNA, children are more at risk because as they grow, their cells divide more frequently than those of adults, perpetuating that damage. But for other substances, such as chloroform, the E.P.A. has determined that children are as likely or less likely to get cancer because of the way it affects organs.