2,2'-iminobis[4,6-diamino-1,3,5-triazine]

Carcinogenicity

Description of key information

Melam is not considered to be carcinogen based on the negative results of mutagenicity studies, the practically non-toxicity in repeated dose toxicity studies and the low exposure.

Justification for classification or non-classification

Melam is not considered to be carcinogen based on the negative results of mutagenicity studies, the practically non-toxicity in repeated dose toxicity studies and the low exposure.

Additional information

According to REACH, Annex X, "A carcinogenicity study may be proposed by the registrant or may be required by the Agency in accordance with Articles 40 or 41 if:

the substance has a widespread dispersive use or there is evidence of frequent or long-term human exposure, and

the substance is classified as mutagen category 3 or there is evidence from the repeated dose study(ies) that the substance is able to induce hyperplasia and/or preneoplastic lesions.

If the substances is classified as mutagen category 1 or 2, the default presumption would be that a genotoxic mechanism for carcinogenicity is likely. In these cases, a carcinogenicity test will normally not be required."

Melam is not genotoxic in two Ames-tests, in two in vitro chromosome aberration assays and in an in vivo micronucleus test. Melam is therefore not classified as mutagen. No toxicity at all and especially also no systemic toxicity was detected in the repeated dose oral toxicity studies even at the high dose of 1000 mg/kg bw.

The exposure of humans is low: Melam has not a wide dispersive use. Melam is exclusively introduced into plastic material during compounding. It is included by this process into a matrix and is no longer available for inhalation or dermal exposure. Melam is used for electronic components in Personal Computers, Televisions, Laptops etc.

Workers: The exposure of workers will be low, as the conditions during manufacturing will prevent an exposure to dust. The exposure is low, even if one takes worst case conditions: For Melam, as for every solid, there exists a general exposure level to prevent irritation of the respiratory tract, that is 10 mg/m3 for inhalable dust and 3 mg/m3 for respirable particles. Respirable particles that are retained in the respiratory tract, will be dissolved in the aqueous mucous layer and mainly be swallowed. It is assumed that a worker inhales 10 m3 of air during a working day and that the average bodyweight of the worker is 70 kg. At an average concentration of 10 mg melam per m3 the worker inhales 100 mg/day or 1.43 mg/kg bw/day.

Consumers: There is no direct contact by hands touching the components. So the only exposure might be inhalation of vapour, escaping from the electronic components. The vapour pressure of melam is very low and only insignificant exposures are expected from this source.

Conclusion: According to the conditions laid down in REACH, Annex X, there is no requirement to propose a carcinogenicity study.