Thursday June 19 3:40 PM EDT

-- Titanium dioxide, a compound whose toxicity remains unclear, is an ingredient found in many sunscreens. Researchers now say the chemical can be absorbed by human skin.

Australian researchers believe "percutaneous (through skin) absorption of titanium can result from the use of sunscreens which contain microfine titanium dioxide," according to a report in Skin & Allergy News, a dermatological newsletter, earlier this year.

Researchers at Westmead Hospital in Westmead, Australia, originally published their findings in the Australasian Journal of Dermatology.

Titanium dioxide is a fine, white powder, used in sunscreens because of its ability to reflect and scatter ultraviolet light. The compound's full effects on human health are still under investigation. The U.S. Government's National Institute for Occupational Safety and Health (NIOSH) labels the chemical " a potential occupational carcinogen." This definition does not include exposures outside the workplace, which are usually of lower levels.

The Australian researchers removed 16 skin tissue samples from the lesions of 13 elderly (averaging 71 years of age) Caucasian patients prior to surgery. All of the patients had applied 8% microfine titanium dioxide sunscreens to the lesion area twice daily for a 2 to 6 week period before tissue sample removal.

The researchers compared titanium levels of those skin samples to levels found in skin samples taken from cadavers. The cadaver samples were removed from the hip area, a spot thought unlikely to have been exposed to sunscreen.

"They found higher levels of titanium in samples taken from patients who use the sunscreen, compared with samples taken from the cadavers," according to Skin & Allergy News.

The Australian study adds to ongoing research into the possible hazards of the compound. In a statement released last July, E. Edward Kavanaugh, president of the Cosmetic, Toiletry, and Fragrance Association (CTFA), said at that time that "the recent publicity raising concern over the safety of sunscreen products is based on incomplete test data."

One of the Australian researchers, Dr. Mei-Heng Tan, seems to agree that more research is required. He told Skin & Allergy News that more information is needed before we understand the risks, if any, of titanium dioxide absorption.

SOURCE: Skin & Allergy News (February 1997, p. 15)