Registration Dossier

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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Administrative data

carcinogenicity, other
Type of information:
other: Expert statement
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Expert statement

Data source

Reference Type:
other: Expert statement
Report date:

Materials and methods

Results and discussion

Applicant's summary and conclusion

Executive summary:

The carcinogenic potential of Tetramethylammonium hydroxide (TMAH) was evaluated based on the available information on the substance and its analogue tetramethylammonium chloride (TMAC) having the same functionality as TMAH with the exception of the chloride anion instead of a hydroxide ion.
There is no information available on in vivo carcinogenic studies on TMAH.
Based on the physicochemical properties of the substance, absorption following an oral, dermal and inhalation exposure cannot be excluded, however, there are no consumer-related uses for the substance; uses at industrial sites and use by professional workers do not lead to a subsequent service life relevant for the respective use and exposure to it by professional workers is highly controlled due to the corrosive nature of the substance.
Reliable studies were identified investigating the genotoxicity potential of TMAH. Results have led to the conclusion that tetramethylammonium hydroxide is negative for mutagenicity in bacteria as well as it does not induce chromosomal aberrations and gene mutations in the tk gene of the L5178Y mouse lymphoma cell line, with or without metabolic activation. Therefore, TMAH is considered not to be a genotoxic carcinogen.
Moreover, following a long-term exposure to the substance (28 days) as well as to its analogue TMAC (90 days) by the oral route, no treatment-related pre-neoplastic or neoplastic lesions were observed as a result of this exposure in rats.
Based on the data presented the results indicate that Tetramethylammonium hydroxide poses no carcinogenic hazard.
This assessment was performed using valid available data and is considered as sufficient in order to conclude on its classification for carcinogenicity, using the rules laid down in the CLP Regulation. Further testing is not considered required.