tert-butyl acrylate

Endpoint summary

Description of key information

Tert-butyl acrylate is irritating to the respiratory system and the skin, but not irritating to the eyes.

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

no guideline followed

Principles of method if other than guideline:

Skin irritation was tested using an internal standard method (BASF test). White Vienna rabbits were used. Usually, 2 animals were treated for 1, 5 and 15 minutes and for 20 hours using occlusive conditions. An application site of 2.5 X 2.5 cm was covered with the liquid test substance.

GLP compliance:

no

Specific details on test material used for the study:

tert. Butylacrylate, stabilized with 0.02 % hydroquinone

Species:

rabbit

Strain:

Vienna White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Breeder
- Weight at study initiation: 2.04 - 2.97 kg


ENVIRONMENTAL CONDITIONS
not reported

Type of coverage:

occlusive

Preparation of test site:

shaved

Vehicle:

unchanged (no vehicle)

Controls:

no

Amount / concentration applied:

ca. 1 mL

Duration of treatment / exposure:

20 h and 1, 5, 15 min

Observation period:

7/8 days

Number of animals:

4 (in two trials)

Details on study design:

TEST SITE
- Area of exposure: 2.5 x 2.5 cm

REMOVAL OF TEST SUBSTANCE
- Washing: The skin area exposed for 20 h was not washed, while the shorter treated areas were washed twice, with Lutrol and Lutrol : water 1:1 solution

Irritation parameter:

erythema score

Remarks:

20 h exposure

Basis:

animal #1

Time point:

24/48 h

Score:

2.5

Max. score:

4

Reversibility:

fully reversible within: 7 days

Irritation parameter:

erythema score

Remarks:

20 h exposure

Basis:

animal #2

Time point:

24 h

Score:

2

Max. score:

4

Remarks on result:

other: animal died before 48h reading

Irritation parameter:

erythema score

Remarks:

20 h exposure

Basis:

animal: animal #3, #4

Time point:

24/48/72 h

Score:

2

Max. score:

4

Reversibility:

fully reversible within: 7 or 8 days (animal #4 or #3, respectively)

Irritation parameter:

edema score

Remarks:

20 h exposure

Basis:

animal #1

Time point:

24/48 h

Score:

2.5

Max. score:

4

Reversibility:

fully reversible within: 7 days

Irritation parameter:

edema score

Remarks:

20 h exposure

Basis:

animal #2

Time point:

24 h

Score:

2

Max. score:

4

Remarks on result:

other: animal died before 48h reading

Irritation parameter:

edema score

Remarks:

20 h exposure

Basis:

animal: #3, #4

Time point:

24/48/72 h

Score:

1.3

Max. score:

4

Reversibility:

fully reversible within: 72 hours

Irritation parameter:

erythema score

Remarks:

15 min exposure

Basis:

animal #1

Time point:

24/48 h

Score:

2.5

Max. score:

4

Reversibility:

fully reversible within: 8 days

Irritation parameter:

erythema score

Remarks:

15 min exposure

Basis:

animal #2

Time point:

24 h

Score:

2

Max. score:

4

Remarks on result:

other: animal died before 48h reading

Irritation parameter:

erythema score

Remarks:

15 min exposure

Basis:

animal #3

Time point:

24/48/72 h

Score:

1.7

Max. score:

4

Reversibility:

fully reversible within: 7 days

Irritation parameter:

erythema score

Remarks:

15 min exposure

Basis:

animal #4

Time point:

24/48/72 h

Score:

1.3

Max. score:

4

Reversibility:

fully reversible within: 7 days

Irritation parameter:

edema score

Remarks:

15 min exposure

Basis:

animal #1

Time point:

24/48 h

Score:

1

Max. score:

4

Reversibility:

fully reversible within: 7 days

Irritation parameter:

edema score

Remarks:

15 min exposure

Basis:

animal #2

Time point:

24 h

Score:

0

Max. score:

4

Remarks on result:

other: animal died before 48h reading

Irritation parameter:

edema score

Remarks:

15 min exposure

Basis:

animal #3

Time point:

24/48/72 h

Score:

0

Max. score:

4

Irritation parameter:

edema score

Remarks:

15 min exposure

Basis:

animal #4

Time point:

24/48/72 h

Score:

0.7

Max. score:

4

Reversibility:

fully reversible within: 48 hours

Irritant / corrosive response data:

See comments in table below.

Other effects:

Reversible clinical signs (apathy and abdominal position with stretched extremities) were seen directly after the 20 h exposure.

Since irritation data are recommended for a 4 h skin exposition, results of the available 20 h and the 15 min exposition will serve as approximation.

Exposure:	20 h
Animal	Reading	Erythema	Edema	Comment
1	24 h	2	2	largely extending beyond the area of exposure; reversible apathy
2	24 h	2	2	largely extending beyond the area of exposure; apathy, followed by abdominal position and convulsions of the extremities before exitus
3	24 h	2	2	abdominal position with stretched extremities for one hour after exposure was finished
4	24 h	2	2	abdominal position with stretched extremities for one hour after exposure was finished
1	48 h	3	2	largely extending beyond the area of exposure
2	48 h	animal died
3	48 h	3	2
4	48 h	3	2
3	72 h	1	0	fine scaling
4	72 h	1	0	fine scaling
3	4 d	1	0	fine scaling
4	4 d	1	0
1	5 d	1	0	largely extending beyond the area of exposure
2	5 d	animal died
1	7 d	0	0	scaling
2	7 d	animal died
3	7 d	1	0	fine scaling
4	7 d	0	0	fine scaling
1	8 d	0	0	scaling
2	8 d	animal died
3	8 d	0	0	fine scaling
4	8 d	0	0	fine scaling
mean	24 - 48 h	2.11	1.56
Exposure:	15 min
Animal	Reading	Erythema	Edema	Comment
1	24 h	2	0	largely extending beyond the area of exposure
2	24 h	2	0	largely extending beyond the area of exposure
3	24 h	2	0
4	24 h	2	2
1	48 h	3	2	largely extending beyond the area of exposure
2	48 h	animal died
3	48 h	2	0
4	48 h	2	0
3	72 h	1	0
4	72 h	0	0
3	4 d	0	0
4	4 d	0	0
1	5 d	2	2	parchment-like
2	5 d	animal died
1	7 d	1	0	rough scaling
2	7 d	animal died
3	7 d	0	0
4	7 d	0	0	fine scaling
1	8 d	0	0	scaling
2	8 d	animal died
mean	24 - 48 h	1.78	0.44

Interpretation of results:

Category 2 (irritant) based on GHS criteria

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Eye irritation

Link to relevant study records

Reference

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

no guideline followed

Principles of method if other than guideline:

Before OECD Guideline 405 was established, eye irritation was tested using an internal method (BASF test). Approximately 50 µL (one drop) of the test substance were applied to the conjunctival sac of one eye in 2 animals. The eyes were not washed out after 24 hours as specified in OECD Guideline 405.

GLP compliance:

no

Specific details on test material used for the study:

tert. Butylacrylate, stabilized with 0.02 % hydroquinone

Species:

rabbit

Strain:

Vienna White

Details on test animals or tissues and environmental conditions:

TEST ANIMALS
- Weight at study initiation: 2.2 - 2.36 kg

ENVIRONMENTAL CONDITIONS
not reported

Vehicle:

unchanged (no vehicle)

Controls:

other: The saline-treated adjacent eye served as control.

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied: 50 µL

Duration of treatment / exposure:

Treatment was once. The eye was left unwashed.

Observation period (in vivo):

2/3 d depending on observed complete reversibility

Number of animals or in vitro replicates:

2

Details on study design:

REMOVAL OF TEST SUBSTANCE
- Washing (if done): not rinsed

Irritation parameter:

cornea opacity score

Basis:

mean

Remarks:

(2 animals)

Time point:

24/48/72 h

Score:

0

Max. score:

4

Reversibility:

other: no effects

Irritation parameter:

iris score

Basis:

mean

Remarks:

(2 animals)

Time point:

24/48/72 h

Score:

0

Max. score:

2

Reversibility:

other: no effects

Irritation parameter:

conjunctivae score

Basis:

mean

Remarks:

(2 animals)

Time point:

24/48/72 h

Score:

0.16

Max. score:

3

Reversibility:

fully reversible within: 48 h

Remarks on result:

other: In one animal, pinhead-sized bleedings of the nictitating membrane were observed after 24 and 48 h, but were reversible within 72 h.

Irritation parameter:

chemosis score

Basis:

mean

Remarks:

(2 animals)

Time point:

24/48/72 h

Score:

0

Max. score:

4

Reversibility:

other: no effects

Irritant / corrosive response data:

Slight conjunctivae redness and chemosis were observed in both animals at the 10 min, 1 h and 3 h readings. Additionally, reversible myosis (1 h and 3 h reading) and questionable corneal opacity (3 h) were observed in one animal.

Interpretation of results:

GHS criteria not met

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Additional information

Skin irritation:

Undiluted tert-butyl acrylate was applied to the skin of rabbits under occlusive conditions for one minute, 5 minutes, 15 minutes and 20 hours. The 1-minute, 5 and 15 minutes exposure resulted in slight erythema after 24 hours, after 8 days only scaling was observed. 20 hours of exposure caused moderate erythema and slight edema at 24 hours, only scaling was observed 8 days after application. 1/4 animals died after the 15 min and 20 h applications, respectively. Mean erythema scores (24-48-72 hours) for the 15-min and 20-hour exposure were 1.78 and 2.11, respectively. Mean edema scores (24-48-72 hours) for the 15-min and 20-hour exposure were 0.44 and 1.56, respectively. The effects were fully reversible within 8 days except for scaling which was observed for the 1-, 5- and 15 -minute and 20-hour applications at the end of the observation period (BASF 1964). Thus, tert-butyl acrylate was assessed to be irritating to the skin.

Eye irritation:

In an eye irritation study in White Vienna rabbits conducted according to an internal study protocol, 50 µL of the undiluted substance were instilled into the eye of 2 rabbits. The adjacent eyes of the same animals were treated with NaCl and served as control. The eyes were not washed out as recommended by the OECD TG 405. Eye reactions were read after 1,  24, 48 and 72  hours. Slight conjunctivitis (Draize grade 1) was noted in one animal after 24 hours. In the other animal, pinhead-sized bleedings of the nictitating membrane were observed after 24 and 48 h, but were reversible within 72 h. The effects were completely reversible within 72 hours (BASF 1964). Tert-butyl acrylate was assessed to be not irritating to the eyes of rabbits.

Respiratory irritation:

In an acute toxicity study and in an inhalation hazard test vapour concentrations of ca. 3 mg/L and higher were irritating to the eyes, nose and respiratory tract (BASF 1979). This is supported by findings reported in a combined subchronic toxicity study with a reproduction / developmental screening test (BASF 2004).

Justification for classification or non-classification

Based on the observed skin irritation the test substance is classified as Skin irrit. 2 H315: Causes skin irritation in accordance with EU Classification, Labeling and Packaging of Substances and Mixtures (CLP) Regulation No. 1272/2008 and as Skin Mild Irrit. 3 H316: Causes mild skin irritation in accordance with GHS classification (GHS UN rev.6, 2015).

 

Based on the observed results classification for eye irritation is not warranted in accordance with with EU Classification, Labeling and Packaging of Substances and Mixtures (CLP) Regulation No. 1272/2008 and GHS classification (GHS UN rev.6, 2015).

 

Based on the observed respiratory irritation in several studies the test substance is classified as STOT Single Exp. 3 H335: May cause respiratory irritation in accordance with EU Classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008 and GHS classification (GHS UN rev.6, 2015).