American-made cigarettes such as Marlboros contain up to twice as much of a cancer-causing chemical as foreign brands, federal health officials said Friday.
The Centers for Disease Control and Prevention compared the levels of the carcinogen nitrosamine in Marlboros, chosen because of their wide availability, and local brands in 13 other countries. In 11 of the countries, the local brands had much lower levels than Marlboro.
CDC officials said the higher nitrosamine levels in American-made cigarettes are a result of way the tobacco is cured and blended.
"What this says to us is it is possible for the manufacturer to lower the levels of this carcinogen," said David Ashley, who led the study, published Friday in the journal Nicotine and Tobacco Research.
The CDC also compared Marlboros, which are made by Philip Morris, with American competitor Doral, manufactured by R.J. Reynolds. Both brands, the most popular in the country, had about the same nitrosamine levels.
Philip Morris said it is working with American growers on developing curing methods to reduce the nitrosamine.
"We're trying to find a way to reduce the harm associated with our products by reducing the level of harmful constituents that smokers inhale," said spokesman Brendan McCormick.
The CDC warned that nitrosamines are not the only carcinogen in cigarette smoke and that "reducing their levels alone does not guarantee a less hazardous cigarette."