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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

Endpoint:
in vitro gene mutation study in bacteria
Remarks:
Type of genotoxicity: gene mutation
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: guideline study - only 4 strains tested

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1994
Report date:
1994

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Principles of method if other than guideline:
The mutagenic potential of m-tolylisocyanate was examined in the Salmonella/microsome test. Bacteria of four histidineauxotrophic Salmonella typhimurium LT2 mutant strains (TA 98, TA 100, TA 1535, and TA 1537) were exposed to doses up to 5000 pg per plate. Both the plate incorporation method and the preincubation method was used.
GLP compliance:
yes
Type of assay:
bacterial reverse mutation assay

Test material

Constituent 1
Chemical structure
Reference substance name:
m-tolyl isocyanate
EC Number:
210-676-0
EC Name:
m-tolyl isocyanate
Cas Number:
621-29-4
Molecular formula:
C8H7NO
IUPAC Name:
1-isocyanato-3-methylbenzene
Details on test material:
purity: 99.73 %

Method

Species / strain
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Additional strain / cell type characteristics:
other: Firstly, they are deep rough since certain lipopolysaccharide side chains are missing in the bacterial cell wall. Secondly, their reduced ability to repair damage from UV light (e.g. thymidine dimers) allows the phenotypic detection of mutation events
Metabolic activation:
with and without
Metabolic activation system:
S-9 mix
Test concentrations with justification for top dose:
plate incorporation assay: 0, 8, 40, 200, 1000, 5000 µg/plate
preincubation assay: 0, 62.5, 125, 250, 500, 1000, 2000 µg/tube
Controls
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
Positive controls:
yes
Positive control substance:
other: sodium azide, nitrofurantoin, 4-nitro- 1,2-phenylene diamine, 2-aminoanthracene
Details on test system and experimental conditions:
IUCLID4 Type: Ames test

Results and discussion

Test results
Species / strain:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
other: Doses up to and including 200 pg per plate did not cause any bacteriotoxic effects
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Remarks on result:
other: other: S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Remarks:
Migrated from field 'Test system'.

Any other information on results incl. tables

Doses up to and including 200 µg per plate did not cause any bacteriotoxic effects: Total bacteria counts remained unchanged and no growth inhibition was observed. The substance revealed weak, strain-specific bacteriotoxic effects at higher doses yet doses up to 1000 µg per plate could still be used for assessment purposes. Substance precipitation occurred at the dose of 500 µg per plate and above. Plates containing 2000 or 5000 µg of the test substance could not be used for assessment purposes.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative
Executive summary:

The mutagenic potential of m-tolylisocyanate was examined in the Salmonella/microsome test. Bacteria of four histidineauxotrophic Salmonella typhimurium LT2 mutant strains (TA 98, TA 100, TA 1535, and TA 1537) were exposed to doses up to 5000 pg per plate. Both the plate incorporation method and the preincubation method was used.

Doses up to and including 200 µg per plate did not cause any bacteriotoxic effects: Total bacteria counts remained unchanged and no growth inhibition was observed. The substance revealed weak, strain-specific bacteriotoxic effects at higher doses yet doses up to 1000 µg per plate could still be used for assessment purposes. Substance precipitation occurred at the dose of 500 µg per plate and above. Plates containing 2000 or 5000 µg of the test substance could not be used for assessment purposes.

There was no evidence for mutagenic effects of m-tolylisocyanate with and without S9 mix. A biologically relevant increase of revertant colony numbers over control levels was not observed. Therefore, m-tolylisocyanate was considered to be non-mutagenic in the Salmonella/microsome test.