Registration Dossier

Administrative data

Description of key information

The slightly soluble and insoluble zinc compounds (i.e., zinc oxide, zinc hydroxide,  zinc phosphate, zinc carbonate, zinc metal and zinc sulphide) are of low acute, dermal and inhalation toxicity not requiring a classification for acute toxicity according to the EC criteria.

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion
Dose descriptor:
LD50
Value:
2 000 mg/kg bw

Acute toxicity: via inhalation route

Endpoint conclusion
Dose descriptor:
LC50
Value:
5.41 mg/m³

Acute toxicity: via dermal route

Endpoint conclusion
Dose descriptor:
LD50
Value:
2 000 mg/kg bw

Additional information

With LD50values consistently exceeding 2,000 mg/kg bw, slightly soluble or insoluble zinc compounds such as zinc oxide (LD50ranges between 5,000 and 15,000mg/kg bw), zinc phosphate (LD50is >5,000mg/kg bw), zinc metal (LD50 >2,000mg/kg bw) or zinc sulphide (LD50is >15,000mg/kg bw), show level of acute oral toxicity. Moreover, zinc oxide and zinc metal were further shown to be of low acute inhalation toxicity (i.e., LC50 values of > 5.41 and 5.7 mg/L/4hrs). Given the common characteristics shared via their solubility characteristics, the remaining slightly soluble zinc compounds are also considered to be of low acute inhalation toxicity.

Of significance for humans from an acute toxicity standpoint is the occurrence of metal fume fever following exposure to ultrafine particles of special grades of zinc oxide in context of very specific operations. According to the response from 11 zinc companies to a questionnaire, there have been no observations of zinc metal fume fever over the last decade and in recent occupational practice. However in light of responsible care and since no studies are available that allow the establishment of a NOAEL for metal fume fever with a reasonable degree of certainty, a LOAEL (5 mg ZnO/m3) for 2 hours (showed the typical metal fume fever symptoms beginning 4 to 8 hours after exposure and disappearing within 24 hours) can be used for metal fume fever based on the study by Gordon et al.(1992).

Justification for classification or non-classification

The slightly soluble and insoluble zinc compounds (i.e., zinc oxide, zinc hydroxide, zinc phosphate, zinc carbonate, zinc metal and zinc sulphide)

are of low acute, dermal and inhalation toxicity not requiring a classification for acute toxicity according to the EC criteria.