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Administrative data

Description of key information

Inhalation: LC50 (rat) > 21.8 mg/L (10557 ppm) (Griffith and Watson, 2009)

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion
Endpoint conclusion:
no study available

Acute toxicity: via inhalation route

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
LC50
Value:
21 800 mg/m³ air
Quality of whole database:
The available information comprises a reliable GLP compliant OECD Guideline study, which is sufficient to fulfil the standard information requirements set out in Annex VII, 8.5, of Regulation (EC) No 1907/2006.

Acute toxicity: via dermal route

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

Inhalation is the only significant route of exposure.

The LC50 determined in a reliable study according to OECD 403 using HsdRccHan:WIST strain rats was greater than 21800 mg/m³ (10557 ppm) after 4 h nose only exposure (Griffith and Watson, 2009). No deaths occurred in three groups of ten rats exposed to 4020, 8420 and 21800 mg/m³ chloromethane followed by a fourteen day observation period. Common abnormalities noted during the study included increased respiratory rate, hunched posture, pilo-erection and wet fur. In the highest dose group isolated occurrences of decreased respiratory rate and occasional laboured respiration were observed. One day after exposure, all animals appeared normal. In the 8420 and 21800 mg/m³ dose group slight bodyweight losses or a reduced bodyweight gain occurred during week 1. With the exception of one female rat from the highest dose group normal development was noted during week 2. Dark patches in the lung and speckled appearance in kidneys were detected amongst several animals at necropsy.

In a mechanistic study performed to evaluate the effect of GSH depletion on chloromethane toxicity in male B6C3F1 mice, a LC50 of 4543 mg/m³ after 6h exposure was determined (Chellman et al., 1986). The recalculated value for a 4h exposure corresponded to 5200 mg/m³.


Justification for selection of acute toxicity – oral endpoint
Since chloromethane is a gas, only inhalation route could be evaluated as no relevant human exposure may occur by oral route.

Justification for selection of acute toxicity – inhalation endpoint
The selected study is the most adequate and reliable study based on overall quality assessment.

Justification for selection of acute toxicity – dermal endpoint
Since chloromethane is a gas, only inhalation route could be evaluated as no relevant human exposure may occur by dermal route.

Justification for classification or non-classification

The available data is conclusive but not sufficient for classification according to DSD (67/548/EEC) and CLP (1272/2008/EC).