WASHINGTON (AP) â€” Saccharin has been dropped from the federal list of cancer-causing chemicals, but tobacco, both smoked and dipped, have been added, along with alcoholic drinks and sunlamps.
The release Monday of the 9th National Toxicology Report on Carcinogens deleted saccharin as a possible cancer-causing chemical, but identified secondhand tobacco smoke, directly inhaled tobacco smoke and smokeless tobacco as known carcinogens.
A statement from the National Institute of Environmental Healthy Sciences said that saccharin was dropped off the list after new studies showed ``no clear association'' between the sweetener and human cancer.
``Two decades ago, when saccharin was shown to produce bladder tumors in rats, it was a prudent, protective step to consider the sweetener to be a likely human carcinogen,'' said Dr. Kenneth Olden, director of the NIEHS and the National Toxicology Program.
But Olden said an advance in scientific understanding ``allows us to make finer distinctions today. ... In other words, with better science we can now make a better call.''
Studies now show that laboratory rat bladder tumors once linked to saccharin are ``not relevant to the human situation,'' Olden said, adding that decades of human saccharin use ``adds to our confidence.''
Saccharin previously had received a clean bill of health from such groups as the American Cancer Society, the American Medical Association, the American Dietetic Association and the American Diabetes Association.
The carcinogen report also delisted ethyl acrylate, a chemical used in the manufacture of latex paints and textiles. It had been listed in 1989 as ``reasonably anticipated to be a human carcinogen.'' A review of lab studies showed the chemical caused cancer in rats only when it was fed to the animals in high concentrations. Human exposure in such a way, the report said, ``is unlikely.''
The report, which identifies a total of 218 cancer threats, formally endorses years of scientific studies that have linked cancer with tobacco.
Additions to the list of ``known human carcinogens'' include environmental, or secondhand, tobacco smoke; directly inhaled tobacco smoke and smokeless tobacco (such as snuff). New items on the list also include alcoholic beverages; sunlamps and sunbeds, and six industrial chemicals and dyes.
Also added to the list was tamoxifen. Although it fights breast cancer, the drug also increases the risk of uterine cancer.
Seven chemicals, including diesel exhaust particulates, were added as substances ``reasonably anticipated to be human carcinogens.'' The other additions to this list are industrial chemicals.
Linking saccharin to cancer originated with 1977 laboratory studies in which male rats fed huge doses of the sweetener developed bladder tumors. Some compared the dosage to a human drinking 800 cans of diet soda daily for a lifetime.
The studies led the Food and Drug Administration call for a ban on saccharin, but Congress in 1977 placed a moratorium on the FDA ban. That moratorium was renewed periodically.
Congress did pass legislation requiring all saccharin products to carry a label warning that the sweetener ``may be hazardous to your health'' because it caused cancer in lab animals.
The 1981 Report on Carcinogens first listed saccharin as an ``anticipated human carcinogen.''
But human studies soon began to question the dangers of the sweetener and in 1991, the FDA withdrew its proposed ban.
With the delisting from the carcinogen report, saccharin supporters will next ask Congress to remove the warning label, said Keith Keeney of the Calorie Control Council, an association of diet food and beverage manufacturers.
Saccharin is the oldest of the common artificial sweeteners. It was discovered by Johns Hopkins University chemist Constantine Fahlberg in 1879 and was used in diets starting early in the 20th century, particularly during wartime when sugar supplies were short. Use increased in the 1950s when diet foods became more popular.
There are three other artificial sweeteners now in wide commercial use â€” aspartame, sucaralose and acesulfame potassium â€” none of which has been linked to cancer, Keeney said.