Registration Dossier

Administrative data

Description of key information

 HEMA is of a low order of acute oral toxicity in studies in rats. No acute dermal toxicity studies are available for HEMA, but due to the structural analogy, the anticipated comparable dermal absorption and the low observed acute toxicity after oral administration of HEMA and HPMA, a reliable study with HPMA is used as read across for HEMA. No acute inhalation toxicity test data are available for HEMA. Taking into account the low vapour pressure, inhalation is not a relevant route of exposure. The low order of toxicity of HEMA in acute oral test would indicate that this material has a low order acute toxicity following inhalation exposure.

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion
Dose descriptor:
LD50
5 564 mg/kg bw

Acute toxicity: via dermal route

Endpoint conclusion
Dose descriptor:
LD50
5 000 mg/kg bw

Additional information

The oral LD50of HEMA in rats was determined to be 5564 mg/kg. This study (Sterner, 1982) was assigned a Klimisch rating of 2, reliable with restriction. Dose-related symptoms included reduction in activity, tremor, disturbance of coordination or gait, reduced muscle tonus in limbs, elevated temperature and piloerection. Other available studies were reviewed and judged to be not reliable or not assignable.

The dermal LD50of HPMA in rabbits was determined to be > 5000 mg/kg. This study (Rohm and Haas 1982) was assigned a Klimisch rating of 2, reliable with restriction. No clinical symptoms of intoxication were noted. Animals’ skin presented with erythema but no edema. Other available studies were reviewed and judged to be not reliable or not assignable. Due to the structural analogy, the anticipated comparable dermal absorption and the low observed acute toxicity after oral administration of HEMA and HPMA, this study with HPMA is used as read across for HEMA.

No acute inhalation toxicity test data are available for HEMA or for HPMA. Taking into account the low vapour pressure and saturated vapour concentration of the two chemicals, inhalation is not a relevant route of exposure as confirmed by actual workplace concentrations (see attachment in IUCLID dataset chapter 13 Assessment reports). Potentially toxic concentrations cannot be reached due to the low vapour pressure (0.08 hPa @ 20°C; see also category document, chapter 5.3.1.2).

Conclusion

HEMA were of a low order of acute oral toxicity in studies in rats. HPMA had a low order of toxicity in rabbits. No acute dermal toxicity studies are available for HEMA, but due to the structural analogy, the anticipated comparable dermal absorption and the low observed acute toxicity after oral administration of HEMA and HPMA, it is concluded that HEMA has a low order of acute dermal toxicity. No acute inhalation toxicity test data are available for HEMA or for HPMA, but none are needed as both of these materials have low acute toxicity by oral and dermal routes. The low order of toxicity of HEMA and HPMA in acute oral and dermal tests would indicate that these materials have a low order of acute toxicity following inhalation exposure.

Justification for classification or non-classification

The oral LD50 of HEMA in rats was determined to be 5564 mg/kg. By read-across to HPMA, the dermal LD50 in rabbits was determined to be > 2000 mg/kg.

Based on the LD50 values, HEMA is not classified for acute toxicity.