2-methylpyridine

Endpoint summary

Description of key information

The substance shows mild to moderate acute toxicity by the oral, dermal and inhalation routes.

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LD50

Value:

950 mg/kg bw

Quality of whole database:

adequate

Acute toxicity: via inhalation route

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LC50

Value:

10 100 mg/m³ air

Quality of whole database:

adequate

Acute toxicity: via dermal route

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LD50

Value:

316 mg/kg bw

Quality of whole database:

adequate

Additional information

The acute oral toxicity in rats (LD50) of 2 -methylpyridine was 810 mg/kg bw in one study, and over 950 mg/kg bw in another study. The acute dermal toxicity (LD50 value) in rabbits of 2 -methylpyridine was between 200 and 316 mg/kg in one study, and was 387 mg/kg in another. The inhalation toxicity in rats (LC50) was over 9.4 mg/L (9400 mg/m3) in one study, but less than 13.2 mg/L in a second study. A third study showed a LC50 over 7618 mg/m3 or 7.6 mg/L (2000 ppm) but less than 15 mg/L (4000 ppm). A point value of just over 10 mg/L (10.1 mg/L, or 10100 mg/m3) is arbitrarily chosen within the boundaries of the studies provided.

Justification for selection of acute toxicity – oral endpoint
experimental data

Justification for selection of acute toxicity – inhalation endpoint
experimental data

Justification for selection of acute toxicity – dermal endpoint
experimental study

Justification for classification or non-classification

2 -Methylpyridine has a harmonized classification in Regulation (EC) No. 1272/2008, Index No. 613 -036 -00 -2 as Acute Category 4 (oral), Acute Category 4 (dermal) and Acute Category 4 (inhalation). These endpoints have an asterisk, and so must be considered minimum classifications. According to the data reviewed for the REACH assessment, 2 -Methylpyridine would be classified as Acute Category 4 (oral), where the LD50 of 950 mg/kg bw falls between 300 and 2000 mg/kg bw, and as Acute Category 3 (dermal) with the LD50 of 316 -384 mg/kg bw falling between 200 and 1000 mg/kg bw. For inhalation toxicity, the data in the three studies spans the boundary between Category 3 (500 < LC50 < 2500 ppm OR 0.5 < LC50 < 2.0 mg/L) and Category 4 (2500 < LC50 < 20,000 ppm OR 10 < LC50 < 20 mg/L). It is most likely that the LD50 is over 2500 ppm or 10 mg/L, and so the substance is classified as Category 4. There is insufficient data to support a change in the harmonized classification, from Category 4. Additionally, a STOT-SE Category 3 (H335) classification for respiratory irritation is included in the harmonized version. Considering the assignment of the substance to acute inhalation toxicity Category 4 and with a respiratory corrosion EUH071 hazard, STOT-SE Category 3 represents over-classification for the endpoint of inhalation toxicity.