Oxybenzone

Endpoint summary

Description of key information

LD50 (oral rat) 12800 mg/kg bw
LD50 (dermal rabbit) > 16000 mg/kg bw
LD50 (intraperitonal mice) > 1600 mg/kg

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records

Reference

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

June-July 1969

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: meets basic scientific principles, well documented information

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 401 (Acute Oral Toxicity)

Deviations:

no

GLP compliance:

no

Test type:

standard acute method

Limit test:

no

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: commercial breeder (SPF)
- Weight at study initiation: 112.5 (104-121) g
- Fasting period before study: no
- Housing: single in MACROLON cages Type III
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum

Route of administration:

oral: gavage

Vehicle:

other: aqueous suspension in 0.5 % carboxymethylcellulose

Details on oral exposure:

Given orally by way of an esophageal tube, in the form of a 16 - 32% aqueous suspension in 0.5% carboxymethyl cellulose.

Doses:

1600, 3200, 6400, 12800 mg/kg

No. of animals per sex per dose:

ten (5 males, 5 females)
Total number of animals: forty (20 males, 20 females)

Control animals:

not specified

Details on study design:

40 rats (20 females, 20 males) were orally exposed at dose levels of 1600, 3200, 6400, 12800 mg/kg. Observations were recorded after 1, 7, 14 days observation period.

Statistics:

standard statistical methods

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 12 800 mg/kg bw

Based on:

test mat.

Mortality:

All the animals survived the 14-day observation period.

Clinical signs:

other: Most of the test animals exhibited sluggishness and/or slept for up to one hour following the application of the substance .Thereafter, no further changes were noted in the general condition and behavior of the animals.

Gross pathology:

One animal presented atelectasis of one of the lung lobes. All the other animals were unremarkable.

Other findings:

no data

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

In conclusion, LD50 after 1, 7 and 14 days of observation was in excess of 12,800 mg/kg in rats by orally.

Executive summary:

Total 40 Wistar rats were exposed test article by orally at dose levels of 1600, 3200, 6400, 12800 mg/kg to assess the potential of acute toxicity. All the animals survived the 14-day observation period. There were no abnormal observations in the body weight during the test. Most of the test animals exhibited sluggishness and/or slept for up to one hour following the application of the substance .And no further changes were noted in the general condition and behavior of the animals.One animal presented atelectasis of one of the lung lobes. All the other animals were unremarkable.

Based on the results, it can be concluded that LD50 of test article was greater than 12800 mg/kg after 1, 7 and 14 days of observation.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

12 800 mg/kg bw

Quality of whole database:

The key study showing an LD50 (oral, rat) of 12800 mg/kg bw is perfectly in line with a supportive study documenting a LD50 (oral, rat) of 11600 mg/kg bw.

Acute toxicity: via inhalation route

Endpoint conclusion

Endpoint conclusion:

no study available

Acute toxicity: via dermal route

Link to relevant study records

Reference

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1953

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study was performed prior to OECD guideline availability and GLP but follows basic scientific principles later adopted by OECD.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

GLP compliance:

no

Test type:

standard acute method

Limit test:

no

Species:

rabbit

Strain:

other: Albino

Sex:

male

Details on test animals or test system and environmental conditions:

Animals were housed individually during study and observation period.

Type of coverage:

semiocclusive

Vehicle:

unchanged (no vehicle)

Details on dermal exposure:

Application to shaved abdominal skin surface of white albino rabbits

Duration of exposure:

18-22 hours, followed by a five day observation period

Doses:

2, 4, 8 and 16 g/kg bw

No. of animals per sex per dose:

5

Control animals:

not required

Statistics:

no statistics was applied

Sex:

male

Dose descriptor:

LD50

Effect level:

> 16 000 mg/kg bw

Based on:

test mat.

Mortality:

One death at the 2 g/kg bw level occured and was probably associated with an intercurrent infection and not due to dermal application of the test material. Other than that no mortality occured.

Clinical signs:

other: Only mild skin irritation of short duration developed in 2 animals during the first 2 days of the study and only in animals of the lowest dose level.

Gross pathology:

Following necropsy and autopsy no significant gross findings were noted.

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

LD 50 (dermal, rabbit): > 16000 mg/kg bw

Executive summary:

In this study for dermal acute toxicity performed with male albino rabbits, no treatment related mortality was observed up to a dose of 16 g/kg bw. Thus the LD50 was set to be greater than 16 g/kg bw.

Only mild skin irritations were noted and only in 2 animals of the low dose group (2 g/kg bw). Also, one animal from this dose group died at day 4 of the observation period. Both observations, mild skin irritation and mortality of one test animal were obviously not treatment related as these occured at the low dose group tested and no skin irritation nor mortality was observed at the higher dose groups.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

16 000 mg/kg bw

Additional information

The substance oxybenzone was investigated for acute toxicity following oral, dermal and intraperitonal application and was found to be practically non-toxic, despite being tested at rather high doses. Thus, oxybenzone is not subject to classification for acute toxicity according to CLP and/or DSD. Data on inhalation toxicity are not available and not required given the low vapour pressure and typical application in oil based skin creams of this product in use.

Justification for selection of acute toxicity – oral endpoint
reliable study on acute oral toxicity

Justification for selection of acute toxicity – dermal endpoint
Only dermal study available

Justification for classification or non-classification

Based on acute oral toxicity data (LD50 rat of 12800 mg/kg) and dermal toxicity data (LD 50 rabbit > 16000 mg/kg) the substance is not subject for classification for acute oral and/or dermal toxicity. No systemic effects were noted in any of the acute studies and hence oxybenzone is also not subject to classification as STOT single exposure. Data for inhalation exposure are lacking but not required and aspiration hazard classification is not required as the substance is not a hydrocarbon. Thus, oxybenzone is not subject to classification and labelling for acute toxicity according to CLP (Regulation EC No 1272/2008) or DSD (Directive 67/548/EEC).