Thermal cracking oil from blends of rubber, fuel oils and paraffin waxes, steam-stripped

Endpoint summary

Description of key information

Studies conducted on Gas oil (polymer-derived), thermal cracked, full range, from which the registered substance is derived via steam stripping, and which is compositionally similar to the registered substance, found the substance to be non-irritating to eyes and non-irritating to skin.

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Study was conducted by a GLP accredited laboratory using a method compatible with OECD Testing Guideline 439. The study was conducted on Gas oil (polymer-derived), thermal cracked, full range, from which the registered substance is derived via steam stripping, and which is compositionally similar to the registered substance.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 439 (In Vitro Skin Irritation: Reconstructed Human Epidermis Test Method)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Species:

other: Episkin reconstructed human epidermis model

Strain:

other: Episkin reconstructed human epidermis model

Details on test animals or test system and environmental conditions:

Episkin reconstructed human epidermis model. Episkin model kit supplied by SkinEthic Laboratories, Lyon, France on 23 April 2013.

Type of coverage:

other: The test item was applied topically to the corresponding tissues ensuring uniform covering.

Vehicle:

unchanged (no vehicle)

Controls:

other: Triplicate tissues treated with 10 µL of DPBS served as the negative controls and triplicate tissues treated with 10 µL of SDS 5% w/v served as the positive controls.

Amount / concentration applied:

TEST MATERIAL
Amount(s) applied (volume or weight with unit): 10 µL

Duration of treatment / exposure:

Exposure: 15 minutes
Post-exposure incubation: 42 hours

Number of animals:

N/A

Details on study design:

REMOVAL OF TEST SUBSTANCE
- Washing (if done): Dulbecco's Phosphate Buffered Saline with Ca++ and Mg++
- Time after start of exposure: 15 minutes

SCORING SYSTEM: Optical density at 540 nm

Irritation / corrosion parameter:

other: other: Relative mean viability

Value:

114.5

Remarks on result:

other:

Remarks:

Basis: mean. Time point: 15 minute exposure. Reversibility: no data. Remarks: Relative mean viability is given in units of percentage (%). (migrated information)

Irritant / corrosive response data:

Irritation response data is calculated based on the optical density of MTT at 540 nm. Viable cells can reduce the yellow tetrazolium salt to a blue formazan dye by mitochondrial succinate dehydrogenase. The quantity of viable cells depends on the irritation potential of the test item.

Item	OD(540) of tissues	Mean OD(540) of triplicate tissues	Standard Deviation of OD(540)	Relative individual tissue viability (%)	Relative mean viability (%)	Standard Deviation of Relative mean viability (%)
Negative Control Item (Dulbecco's Phosphate Buffered Saline with Ca++ and Mg++)	0.771	0.0748	0.021	103.1	100	2.9
	0.743			99.3
	0.729			97.5
Positive Control Item (Sodium Dodecyl Sulphate 5% w/v)	0.075	0.076	0.012	10	10.2	1.6
	0.065			8.7
	0.089			11.9
Test Item	0.888	0.856	0.043	118.7	114.5	5.7
	0.808			108
	0.873			116.7

Interpretation of results:

not irritating

Remarks:

Migrated information Criteria used for interpretation of results: OECD GHS

Conclusions:

The relative mean viability of the test item treated tissues was 114.5% after the 15-minute exposure period. The test item was considered to be a non-irritant.

Executive summary:

The in vitro skin irritation of the test substance was determined in accordance with the OECD Guideline for Testing of chemicals 439.

The principle of the assay was based on the measurement of cytotoxicity in reconstructed human epidermal cultures following topical exposure to the test item by means of the MTT reduction assay. The relative mean viability of the test item treated tissues was 114.5% after the 15-minute exposure period. The test item was considered to be a non-irritant.

Gas oil (polymer-derived), thermal-cracked, full-range and Thermal cracking oil from blends of rubber, fuel oils and paraffin waxes, steam-stripped are two very closely related substances. They consist of hydrocarbons having carbon numbers predominantly in the same range (C7 to C32) and boil over a very similar temperature range. The oils contain a relatively large proportion of substituted aromatic hydrocarbons (between 62 and 70%), particularly 1-ring aromatic hydrocarbons. Detailed analytical characterisation shows that the oils have a significant number of individual components in common. Both oils are produced by thermal cracking of the same range of hydrocarbon feedstocks at a temperature of 450-500°C. Thermal cracking oil from blends of rubber, fuel oils and paraffin waxes, steam-stripped differs from Gas oil (polymer-derived), thermal-cracked, full-range in that it has been through a steam-stripping process that removes a proportion of the lower boiling components. In addition to their composition and similar manufacturing process, testing has revealed that the two oils have very similar physico-chemical parameters, especially their solubility in water which is in the region of 3 mg/l suggesting that the two substances might be expected to behave similarly in biological and environmental aqueous environments.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Link to relevant study records

Reference

Endpoint:

eye irritation

Remarks:

other: SkinEthic Reconstructed Human Corneal Epithelial Model

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Study was conducted by a GLP accredited laboratory using the SkinEthic Reconstructed Human Corneal Epithelial Model, as described in the scientific article "Prevalidation of a new in vitro reconstituted human cornea model to assess the eye irritating potential of chemicals" by Van Goethem & al., Toxicology in Vitro 20 (2006) 1–17. The study was conducted on Gas oil (polymer-derived), thermal cracked, full range, from which the registered substance is derived via steam stripping, and which is compositionally similar to the registered substance.

Qualifier:

according to guideline

Guideline:

other: SkinEthic Reconstructed Human Corneal Epithelial Model

Deviations:

yes

Remarks:

Freeze killed tissues not used for quantitative correction of results, and dosing occurred on day 8 instead of day 7. Deviations were not considered to have affected the study.

Principles of method if other than guideline:

The experimental design of the study consists of a test for direct reduction of MTT (3-[4,5 dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide) by the test item followed by the main test.

For the main test, triplicate SkinEthic tissues were treated with 30 µL of the test item for 10 minutes. Triplicate tissues treated with 30 µL of Solution A (supplied by SkinEthic) served as the negative control and triplicate tissues treated with 30 µL of 2% w/v Sodium Dodecyl Sulphate (SDS) served as the positive control.

At the end of the exposure period each SkinEthic tissue was rinsed. The rinsed tissues (two per group) were taken for MTT loading. The remaining tissues were retained for possible histopathology. Following MTT loading the reduced MTT was extracted from the tissues.

After extraction the absorbency of triplicate aliquots of the extracted MTT solution for each SkinEthic tissue was measured. The optical density was measured at 540 nm (OD540). Data are presented in the form of percentage viability (MTT conversion relative to negative controls).

The test item was classified according to the following criteria:
I) If the percentage relative mean tissue viability was ≥60% the test item was considered to be non irritant (NI).
II) If the percentage relative mean tissue viability was <60% the test item was considered to be irritant (I).

GLP compliance:

yes (incl. QA statement)

Species:

other: SkinEthic Reconstructed Human Corneal Epithelial Model

Strain:

other: SkinEthic Reconstructed Human Corneal Epithelial Model

Details on test animals or tissues and environmental conditions:

SkinEthic Reconstructed Human Corneal Epithelial Model (HCE, SkinEthic Laboratories, Lyon, France), received 22 May 2013

Vehicle:

unchanged (no vehicle)

Controls:

other: Triplicate tissues with 30 µL of Solution A served as the negative control and triplicate tissues treated with 30 µL of 2% w/v Sodium Dodecyl Sulphate (SDS) served as the positive control.

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 30 µL

Duration of treatment / exposure:

10 minutes

Number of animals or in vitro replicates:

N/A

Details on study design:

REMOVAL OF TEST SUBSTANCE
Washing (if done): Dulbecco's Phosphate Buffered Saline
Time after start of exposure: 10 minutes

SCORING SYSTEM: Optical density at 540 nm

TOOL USED TO ASSESS SCORE: filter photometer (Anthos 2001 microplate reader)

Irritation parameter:

other: Relative Mean Viability (%)

Basis:

mean

Time point:

other: 10 minutes

Score:

108.8

Reversibility:

not specified

Irritant / corrosive response data:

The relative mean viability of the test item treated tissues after a 10 minute exposure period was 108.8%.

Other effects:

It was considered unnecessary to proceed with tissue histopathology

Item	OD(540) of Individual Tissue	Mean OD(540)	Relative Mean Viability (%)
Negative Control	0.902	0.927	100
	0.952
Positive Control	0.073	0.065	7
	0.057
Test Item	1.039	1.009	108.8
	0.978

Interpretation of results:

not irritating

Remarks:

Migrated information Criteria used for interpretation of results: other: According to study plan

Conclusions:

The relative mean viability of the test item treated tissues after a 10 minute exposure period was 108.8%. According to the study plan followed the test item was considered to be non-irritant.

Executive summary:

The in vitro eye irritation of the test substance was determined in accordance with the SkinEthic Reconstructed Human Corneal Epithelial Model, as described in the scientific article "Prevalidation of a new in vitro reconstituted human cornea model to assess the eye irritating potential of chemicals" by Van Goethem & al., Toxicology in Vitro 20 (2006) 1–17. The experimental design of the study consists of a test for direct reduction of MTT (3 [4,5 dimethylthiazol-2 -yl]-2,5 -diphenyl-tetrazolium bromide) by the test item followed by the main test. The relative mean viability of the test item treated tissues after a 10 minute exposure period was 108.8%. According to the study plan followed the test item was considered to be non-irritant.

Gas oil (polymer-derived), thermal-cracked, full-range and Thermal cracking oil from blends of rubber, fuel oils and paraffin waxes, steam-stripped are two very closely related substances. They consist of hydrocarbons having carbon numbers predominantly in the same range (C7 to C32) and boil over a very similar temperature range. The oils contain a relatively large proportion of substituted aromatic hydrocarbons (between 62 and 70%), particularly 1-ring aromatic hydrocarbons. Detailed analytical characterisation shows that the oils have a significant number of individual components in common. Both oils are produced by thermal cracking of the same range of hydrocarbon feedstocks at a temperature of 450-500°C. Thermal cracking oil from blends of rubber, fuel oils and paraffin waxes, steam-stripped differs from Gas oil (polymer-derived), thermal-cracked, full-range in that it has been through a steam-stripping process that removes a proportion of the lower boiling components. In addition to their composition and similar manufacturing process, testing has revealed that the two oils have very similar physico-chemical parameters, especially their solubility in water which is in the region of 3 mg/l suggesting that the two substances might be expected to behave similarly in biological and environmental aqueous environments.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

The in vitro skin irritation of the test substance was determined in accordance with the OECD Guideline for Testing of chemicals 439.

The principle of the assay was based on the measurement of cytotoxicity in reconstructed human epidermal cultures following topical exposure to the test item by means of the MTT reduction assay. The relative mean viability of the test item treated tissues was 114.5% after the 15-minute exposure period. The test item was considered to be a non-irritant.

The in vitro eye irritation of the test substance was determined in accordance with the SkinEthic Reconstructed Human Corneal Epithelial Model, as described in the scientific article "Prevalidation of a new in vitro reconstituted human cornea model to assess the eye irritating potential of chemicals" by Van Goethem & al., Toxicology in Vitro 20 (2006) 1–17. The experimental design of the study consists of a test for direct reduction of MTT (3 [4,5 dimethylthiazol-2 -yl]-2,5 -diphenyl-tetrazolium bromide) by the test item followed by the main test. The relative mean viability of the test item treated tissues after a 10 minute exposure period was 108.8%. According to the study plan followed the test item was considered to be non-irritant.

Gas oil (polymer-derived), thermal-cracked, full-range and Thermal cracking oil from blends of rubber, fuel oils and paraffin waxes, steam-stripped are two very closely related substances. They consist of hydrocarbons having carbon numbers predominantly in the same range (C7 to C32) and boil over a very similar temperature range. The oils contain a relatively large proportion of substituted aromatic hydrocarbons (between 62 and 70%), particularly 1-ring aromatic hydrocarbons. Detailed analytical characterisation shows that the oils have a significant number of individual components in common. Both oils are produced by thermal cracking of the same range of hydrocarbon feedstocks at a temperature of 450-500°C. Thermal cracking oil from blends of rubber, fuel oils and paraffin waxes, steam-stripped differs from Gas oil (polymer-derived), thermal-cracked, full-range in that it has been through a steam-stripping process that removes a proportion of the lower boiling components. In addition to their composition and similar manufacturing process, testing has revealed that the two oils have very similar physico-chemical parameters, especially their solubility in water which is in the region of 3 mg/l suggesting that the two substances might be expected to behave similarly in biological and environmental aqueous environments.

Justification for selection of skin irritation / corrosion endpoint:
A study was conducted in a GLP lab according to OECD 439 on Gas oil (polymer-derived), thermal cracked, full range, from which the registered substance is derived via steam stripping, and which is compositionally similar to the registered substance.

Justification for selection of eye irritation endpoint:
A study was conducted in a GLP lab according to the SkinEthic Reconstructed Human Corneal Epithelial Model on Gas oil (polymer-derived), thermal cracked, full range, from which the registered substance is derived via steam stripping, and which is compositionally similar to the registered substance.

Justification for classification or non-classification

In the skin irritation study the relative mean viability of the test item treated tissues was 114.5% after the 15-minute exposure period. The test item was considered to be a non-irritant to skin. In the eye irritation study the relative mean viability of the test item treated tissues after a 10 minute exposure period was 108.8%. According to the study plan followed the test item was considered to be non-irritant to eyes.