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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

Description of key information

 - With LD50values consistently exceeding 2,000 mg/kg bw, zinc oxide (LD50ranges between 5,000 and 15,000mg/kg bw), shows very low level of acute oral toxicity. 

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records
acute toxicity: oral
Type of information:
experimental study
Adequacy of study:
key study
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Used in EU risk assessment for zinc oxide, limited study details provided
equivalent or similar to guideline
OECD Guideline 401 (Acute Oral Toxicity)
GLP compliance:
not specified
Test type:
standard acute method
Limit test:
Details on test animals or test system and environmental conditions:
no information
Route of administration:
oral: gavage
not specified
Details on oral exposure:
single dose by oral gavage and observed for 14 days
single dose of 15 gZnO/kg bw
No. of animals per sex per dose:
10 males
Control animals:
not specified
Details on study design:
no further information
no data
Preliminary study:
no further information
Dose descriptor:
Effect level:
> 15 000 mg/kg bw
no mortality
Clinical signs:
other: ruffled fur
Gross pathology:
no adverse signs of toxicity
Other findings:


Interpretation of results:
practically nontoxic
Migrated information Criteria used for interpretation of results: EU
LD50 >15,000 mg ZnO/kg bw was determined.
Executive summary:

In an acute oral study, ten male Wistar rats received a single dose of 15 g ZnO/kg bw by gavage. No mortality occurred. Signs of toxicity were ruffled fur, decreased body weights and diarrhoea. The LD50value for rats was >15 g ZnO/kg bw. No furher information available.

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
5 000 mg/kg bw

Additional information

- With LD50values consistently exceeding 2,000 mg/kg bw, zinc oxide (LD50ranges between 5,000 and 15,000mg/kg bw), shows very low level of acute oral 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 such as cutting or welding of galvanised steel. Metal fume fever is exclusively associated with freshly formed ultrafine particulate zinc oxide (<0.1 µm). As these ultrafine particles (nanoparticles) rapidly agglomerate to bigger particles, which are normally encountered at production and processing sites, at these sites there is no indication for metal fume fever. 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 (EU RAR, 2004a-f). 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

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