The researchers studied the women’s hemoglobin adducts to determine their long-term exposure to toxic compounds that come from hair-dressing dyes. (Hemoglobin attaches to the cancer-causing molecules in hair dyes, allowing researchers to obtain clear blood readings.)
Researchers find carcinogenic toluidine clinging to hemoglobin in some hairdressers
These permanent, oxidative hair dyes work by combining with hydrogen peroxide, setting off a chemical reaction between dye couplers and aromatic amines. When the blood of all three groups was tested for these potentially carcinogenic compounds called aromatic amines, the researchers found very few distinctions. Only one compound stood out. One of the toxic aromatic amines found clinging to the hairdresser’s hemoglobin was toluidine. This carcinogen was found at higher levels in the blood of hair dressers in correlation with how often they used perm chemicals. In fact, the researchers isolated toluidines in one hair-waving product; the toluidines were found in the fixative and a mixture of fixative and perming lotion.
The American Conference of Governmental Industrial Hygienists has confirmed that toluidine causes cancer in animals. The National Institute for Occupational Safety and Health backs up the claims, warning consumers to keep exposure to toluidine as low as possible.
Ortho-toluidine (o-toluidine) was of greatest concern, denoted by the chemical formula CH3C6H4NH2.
“The measured levels of o-toluidine in blood among hairdressers were in general low, however, exposure to o-toluidine should be kept as low as possible since it is a carcinogenic compound,” said researcher Gabriella M. Johansson.
Light hair dye products also increased toluidine levels in hairdressers
In the study, the more a hairdresser used perm chemicals and light hair dyes, the higher their blood toluidine levels. Darker hair dyes were thought to possess the highest level of carcinogens, but permanent light hair dyes were just as toxic. Exposure to semi-permanent hair dyes did not increase toluidine levels.
Johansson stated, “In the late 1970s, regulatory actions were taken in (Europe) and carcinogenic aromatic amines were forbidden for use as hair dye ingredients. Whether this still is a problem for modern hair dyes is debated.”
O-toluidine is no laughing matter. The CDC reports that the toxic compound can either be inhaled, absorbed through the skin or enter the body through the eyes. The potential impact of o-toluidine includes dizzy spells, blood in the urine, weakness, exhaustion and headache. Exposure to the carcinogen is highly discouraged.
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