Registration Dossier

Administrative data

Description of key information

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not sensitising)
Additional information:

Early studies in the open literature included investigations using the Freunds Complete Adjuvant Test, a no longer acceptable test procedure, together with inadequately described test substance that, although described as Rosin, was oxidized rosin. Human studies used oxidized rosin as challenge substance. As oxidized rosin is not the substance being registered, and since the sensitization potential of Rosin, Hydrogenated rosin and their salts (together with supporting information on Rosin, oligomers) has been extensively tested in acceptable GLP compliant tests, these early studies have been omitted from this dossier. Results from other, more relevant investigations are summarised briefly below.

Rosin

In a skin sensitization study using the Local Lymph Node Assay, groups of female mice were given daily applications of 0.25, 2.5, or 25% (w/v) Gum Rosin (Rosin) in butanone which was applied to the dorsal surface of each ear for 3 consecutive days (SafePharm Laboratories Ltd, 2002a). A control group received the vehicle only in the same manner. On Day 5, 3HTdR was injected into the tail vein, the auricular lymph nodes collected 5 hr later, and a single cell suspension prepared. 3HTdR incorporation by the cells was determined, and the Stimulation Index (SI) calculated for each dose of the test substance. A test substance is considered positive for sensitization if the test results produce a threefold or greater increase in the SI. In this study, a SI of less than 3 was recorded for each of the three test concentrations. Based on the results, Gum Rosin was not a moderate or strong skin sensitizer in mice, and therefore, lacks a significant potential to cause skin sensitization.

In a study using the Guinea Pig Maximization Test method, 20 female guinea pigs assigned to the test group were induced by intradermal injections containing 3% Gum Rosin-167 (Rosin) in olive oil (EViC-CEBA 1994a). In addition, these guinea pigs were topically induced with a 25% concentration of the test substance in vaseline oil. Along with the test animals, a group of 10 female control animals, previously not induced, were challenged topically for 24 hours with concentrations of 0, 0.1, 0.5, 1.0, and 2.0% of the test substance in vaseline oil. Skin examinations at 24 and 48 hours after the completion of the challenge exposures indicated that concentrations above 0.1% caused a primary irritant effect characteristic to both the control and treated animals. When the test substance/vehicle was applied to the skin at a concentration of 0.1%, no local irritation reaction was observed in the treated group of animals previously induced with the test substance. In contrast, the presence of slight erythema was noted in 30% (24 hours) and 20% (48 hours) of control animals at this challenge dose during the two successive readings. Reactions of similar nature were observed in 20% of control animals at the vehicle only application sites. Therefore, only skin reactions noted following application of 0.1% test substance in the vehicle at challenge were considered as valid responses to sensitization as opposed to signs of local irritation. At this challenge level, the percentage of reactive animals in the treated group was 0%, which was below the 30% reaction seen in the control animals. Based on these findings, Gum Rosin-167 was not considered to be a skin sensitizer to guinea pigs, and therefore, lacks a significant potential to cause skin sensitization.

In a Guinea Pig Maximization Test method, 20 female guinea pigs assigned to the test group were induced by intradermal injections containing 3% RESIGRAL No. 199 (Rosin) in olive oil (EViC-CEBA, 1994b). In addition, these animals were topically induced with a 25% concentration of the test substance in vaseline oil. Along with the test animals, a group of 10 female control animals, previously not induced with the test substance, were challenged topically for 24 hours with concentrations of 0, 0.1, 0.5, 1.0, and 2.0% RESIGRAL No. 199 in vaseline oil. Skin examinations at 24 and 48 hours after the completion of the challenge exposures indicated that concentrations above 0.5% caused a primary irritant effect characteristic to both the control and treated animals. When the test substance/vehicle was applied to the skin at a concentration of 0.1 or 0.5%, a local irritation reaction was observed for only one animal at one observation point in the 0.5% group among animals previously induced with the test substance. No reactions were observed in treated or control animals at the vehicle-only application sites. Only skin reactions noted following application of 0.1 and 0.5% test substance in the vehicle at challenge were considered as valid responses to sensitization as opposed to signs of local irritation. At these challenge concentrations, the percentage of reactive animals in the treated group was 0-5%. Based on these findings, RESIGRAL No. 199 was not considered to be a skin sensitizer to guinea pigs, and therefore, lacks a significant potential to cause skin sensitization.

In a Guinea Pig Maximization Test using Pexite WG Wood Rosin (Rosin), 10 male and 10 female guinea pigs assigned to the test group were induced by intradermal injections of a 10% test substance in diethyl phthalate (Hill Top Research Inc., 1996a). In addition, these guinea pigs were topically induced with a 40% concentration of Pexite WG Wood Rosin in vehicle. Along with the test animals, a group of 5 male and 5 female naïve control animals, previously not induced with the test substance, were challenged topically for 24 hours with concentrations of 3, 10, 30, and 40% in diethyl phthalate. Another group of 5 males and 5 females assigned to the vehicle control group were induced and challenged with only diethyl phthalate. Observations at 24 and 48 hours after the completion of the challenge exposure indicated a single positive sensitization reaction at the 40% application site at the 48-hour reading for 1 of the 20 test animals. No other positive sensitization reactions were recorded for the remaining test animals or for any of the control animals. Based on the results of this study, Pexite WG Wood Rosin was not considered to be a skin sensitizer in guinea pigs, and therefore, lacks a significant potential to cause skin sensitization.

In a skin sensitization study using the Guinea Pig Maximization Test method, 20 female guinea pigs assigned to the test group were induced by intradermal injections (Day 0) with a 10% concentration of Gum Rosin (Rosin) in olive oil (Central Toxicology Laboratory, 1997h). In addition, these guinea pigs were topically induced (Day 7) with a 40% concentration of the test substance in olive oil. Along with the test animals, a group of 10 female control animals, previously not induced with the test substance, were challenged topically for 24 hours with concentrations of 3, 10, 30, and 40% of the test substance in olive oil. Skin examinations at 24 and 48 hours after the completion of the challenge exposure indicated no positive sensitization reactions in the test or negative control groups. Based on the results of this study, Gum Rosin was not considered to be a skin sensitizer to guinea pigs, and therefore, lacks a significant potential to cause skin sensitization.

In a Guinea Pig Maximization Test, 20 male guinea pigs assigned to the test group were induced by intradermal injections (Day 0) with a 10% concentration of Gum Rosin (Rosin) in olive oil (Central Toxicology Laboratory, 1997d). In addition, these animals were topically induced (Day 7) with a 75% concentration of the test substance in paraffin wax. On Day 21, the test animals and a group of 10 male control animals, previously not induced with the test substance, were challenged with concentrations of 0, 10, 30, and 75% of the test substance in paraffin wax. Skin examinations at 24 and 48 hours after the completion of the challenge exposure indicated scattered mild redness (Grade 1), noted at the 75% application site for 2/20 test animals at the 24-hour reading and at the 30% application site for 1/20 test animals at the 24-hour reading. There was no erythematous response at any of the other application sites at either examination time for the test group or the control group. The percentage of animals responding in the control group was subtracted from the percentage responding in the test group, to give a net percentage response. The net percentage responses were calculated to be 10% for sites administered a 75% concentration of the test substance and 5% for sites administered a 30% concentration of the test substance; when analyzed using Fisher's Exact Test, the responses were not statistically significant. The net percentages for sites administered concentrations of 0 or 10% of the test substance were 0%. Based on the results of this study, Gum Rosin was not considered to be a skin sensitizer in guinea pigs.

In a skin sensitization study using the Guinea Pig Maximization Test method, 20 male guinea pigs assigned to the test group were induced by intradermal injections (Day 0) with a 10% concentration of Pexite WG Wood Rosin (Rosin) in olive oil (Central Toxicology Laboratory, 1997e). In addition, these guinea pigs were topically induced (Day 7) with a 30% concentration of the test substance in olive oil. On Day 21, the test animals, along with a group of 10 male control animals previously not induced with the test substance, were challenged topically for 24 hours with concentrations of 10 and 30% Pexite WG Wood Rosin in olive oil. Skin examinations at 24 and 48 hours after the completion of the challenge exposure indicated scattered mild redness (Grade 1) at the 30% application site for 1/20 animals at both the 24- and 48-hour readings. No other skin reactions were evident for the remaining 19 test animals or for any of the 10 control animals. The net percentage response was calculated to be 5% for application sites dosed with 30% test substance and 0% for application sites dosed with 10% test substance. Based on the results of this study, Pexite WG Wood Rosin was not considered to be a skin sensitizer in guinea pigs, and therefore, lacks a significant potential to cause skin sensitization.

In a study using Pexite 135 Wood Rosin (Rosin), 20 male guinea pigs assigned to the test group were induced by intradermal injections (Day 0) with a 10% concentration of test substance in olive oil (Central Toxicology Laboratory, 1997c). In addition, these animals were topically induced (Day 7) with a 40% concentration of the rosin in olive oil. Along with the test animals, a group of 10 male control animals, previously not induced with the test substance, were challenged topically for 24 hours with concentrations of 25 and 40% of the test substance in olive oil. Skin examinations at 24 and 48 hours after the completion of the challenge exposure indicated scattered mild redness (Grade 1) at the 25% application sites for 1 of the 20 animals at the 24- and 48-hour readings and at the 40% application sites for another of the 20 animals at the 24- and 48-hour readings. No other skin reactions were evident for the remaining test animals or for any of the 10 control animals. The net percentage response was calculated to be 5% for application sites dosed with 25% test substance and 5% for application sites dosed with 40% test substance (different animals affected). Based on the results of this study, Pexite 135 Wood Rosin was not considered to be a skin sensitizer in guinea pigs, and therefore, lacks a significant potential to cause skin sensitization.

Two skin sensitization studies using the Guinea Pig Maximization Test were reported by Central Toxicology Laboratory (1997g) for Gum Rosin (Rosin). The studies differed in the concentration of test substance used for induction (3% or 10% in vehicle and Freund's Complete Adjuvant) and in the sex of the animals (males in one study, females in the other). In addition, the test guinea pigs were topically induced one week later with a 30% concentration of the test substance in vehicle. Along with the test animals, a group of 10 control animals per study, previously not induced with the test substance, were challenged with concentrations of 0, 3, 10, and 30% of the test substance and skin examinations made at 24 and 48 hours post-challenge. One test animal responded to the vehicle with slight (Grade 1) erythema, but none of the animals challenged with the test substance responded positively. Based on the results of these studies, Gum Rosin was not considered to be a skin sensitizer to guinea pigs, and therefore lacks a significant potential to cause skin sensitization.

In a skin sensitization study conducted using the Buehler method, two groups of 20 guinea pigs assigned to test groups were induced three times (once/week for 6 hours) by topical administration of a 10% or 30% concentration of Gum Rosin (Rosin) in a vehicle (Central Toxicology Laboratory, 1997f). In addition, two groups of 10 guinea pigs assigned to control groups received only the vehicle during the three induction applications. Along with the test animals, the controls (previously not induced with the test substance) were challenged topically with concentrations of 3, 10, and 30% of the test substance in the vehicle for an exposure period of 6 hours. Skin examinations at 24 and 48 hours after the completion of the challenge exposure indicated no evidence of skin reactions at the application sites. Therefore, Gum Rosin was not considered to be a skin sensitizer to guinea pigs, and therefore, lacks a significant potential to cause skin sensitization.

In contrast to the preceding results, positive results were reported for a Guinea Pig Maximization Test conducted on a sample identified as Wood Rosin (Rosin) (Central Toxicology Laboratory, 1997i). Indications of skin sensitization were obtained when previously induced animals were challenged with a solution containing 40% test substance, but not when challenged with 30, 10, or 3% solutions. Subsequently, it was determined that the sample identified as Wood Rosin was oxidized and degraded and therefore, was not representative of the substance being evaluated. The results obtained in this study are therefore considered erroneous and unreliable, and should be disregarded when reviewing the biological effects of Wood Rosin.

Rosin, Hydrogenated

In a test procedure modified from the Guinea Pig Maximization Test protocol, 15 guinea pigs (test group) and 15 guinea pigs (control) were intradermally injected with Freund's Complete adjuvant and topically exposed via scarified skin to 0.5 g of Hydrogral (Rosin, hydrogenated) as supplied (Biogir S. A., 1993a). The modification was necessary since it was not possible to inject the test substance. Seven days later, the animals were exposed topically to sodium lauryl sulfate to elicit a mild irritation response, and the following day the neat test substance was topically applied for 48 hours under semi-occlusion. Three weeks after the induction period, the animals were challenged with 25 and 50% of the test substance in paraffin oil. No signs of irritation were noted in any animal 24 or 48 hours after removal of the test substance. Under the conditions of the study, the test substance did not indicate a potential for dermal irritation or sensitization.

In a Guinea Pig Maximization Test, 18 guinea pigs (test group) and 12 guinea pigs (control group) were intradermally injected with Freund's adjuvant, and the test group exposed topically to 0.5 mL of Staybelite Resin-E (Rosin, hydrogenated) under occlusion (Biogir S. A., 1993b). On Day 7, the animals were exposed topically to a 10% solution of sodium lauryl sulfate to elicit an irritation response and the following day neat test substance was topically applied in contact with the skin for 48 hours. Three weeks after the induction period, the animals were challenged with 50 and 25% solutions of the test substance in acetone. All animals exhibited an irritation response that was believed to be from the vehicle, acetone. Subsequently, a rechallenge was performed with the test substance in 90% alcohol at concentrations of 50, 25, and 12.5%. Minimal irritation was only seen at 24 hours during the rechallenge phase and in only one treated and one control animal in the 25% groups. Since it did not occur in a dose dependent manner, it was considered unrelated to the test substance. Under the conditions of the study, the test substance did not indicate a potential for dermal irritation and/or sensitization.

In another Guinea Pig Maximization Test on Hydrogenated Gum Rosin (Rosin, hydrogenated), 20 guinea pigs (test group) and 10 guinea pigs (control group) were intradermally injected with Freund's Complete adjuvant, 10% Hydrogenated Gum Rosin in olive oil, and 10% Hydrogenated Gum Rosin in olive oil with Freund’s Complete adjuvant (1:1) (Central Toxicology Laboratory, 1997a). The animals were exposed topically to a 10% solution of sodium lauryl sulfate to elicit an irritation response and the following day, 40% test substance w/v was topically applied for 48 hours. Two weeks after the induction period, the animals were challenged with 3, 10, 30, and 40% w/v solution of the test substance in olive oil. No signs of irritation were noted in any animal 24 or 48 hours post-challenge. Under the conditions of the study, Hydrogenated Gum Rosin did not indicate a potential for dermal irritation and/or sensitization.

In a Klimisch 3 (not reliable), human repeat insult patch test, 53 panelists were exposed to Foral AX (Rosin, hydrogenated) at 0.2 mL (50% solution in corn oil) under occlusion for three 23 hour periods per week for three weeks (Industrial Bio-Test Laboratories Inc., 1977). After 23 hours of exposure, the patches were removed, and 23-72 hours after patch application, the sites were graded for irritation. After a rest period of 12 days, the panelists were patched on a naïve site (adjacent to induction patch) with the test substance to determine sensitization potential. No irritation was seen in any panelists during the irritation or the sensitization portion of the test. Under the conditions of the study, Foral AX did not indicate a potential for dermal irritation and/or sensitization.

Rosin, reaction products with formaldehyde

The sensitisation potential of Rosin, reaction products with formaldehyde (CAS No. 91081-53-7) has been studied in the guinea pig in two GLP-compliant, guideline (or near guideline) studies. Results from these investigations are summarised briefly below.

In a skin sensitization study performed using the method described by Buehler, a group of 20 female guinea pigs was induced three times (once/week for 6 hours) by topical application of a 30% w/v preparation of UNITAC 70 (Rosin, reaction products with formaldehyde) in a corn oil vehicle (Central Toxicology Laboratory, 1995a). A group of 10 female guinea pigs served as study controls and received only the vehicle during the three induction applications. All animals were challenged topically with concentrations of 3 and 10% w/v of the test material in the vehicle for an exposure period of 6 hours. Skin examinations at 24 and 48 hours after the completion of the challenge exposure indicated the test substance elicited an irritant response at the 10% challenge sites in both control and test animals. Since the response in control animals was greater than that observed in the test animals, this was considered to be an irritant rather than a sensitization response. At the 3% challenge sites, only a single test animal (1/20) had a slight skin response and no skin reactions were evident in the control group of animals. Under the conditions of this study, Rosin, reaction products with formaldehyde was not considered to be a skin sensitizer in guinea pigs.

In a skin sensitization study using the Guinea Pig Maximization Test method, 20 female guinea pigs assigned to the test group were induced by intradermal injections containing 10% formaldehyde treated TOR (Rosin, reaction products with formaldehyde) in olive oil (Central Toxicology Laboratory, 1997b). In addition, the guinea pigs were topically induced with a 75% w/v concentration of the test material in olive oil. A group of 10 female control animals were treated identically except that olive oil alone was used instead of the test solutions containing the test material. All animals were challenged topically for 24 hours with concentrations of 10, 25, 50, and 75% w/v of the test material in olive oil. Skin examinations at 24 and 48 hours after the completion of the challenge exposures indicated that concentrations of 50 and 75% w/v test material in the vehicle caused scattered mild redness in only 2 of 20 test animals. The net percentage response was calculated to be 10% and was not statistically significant. When the test substance was applied to the skin at a concentration of 10 or 25% w/v, no skin reactions were evident. No skin reactions were noted in control animals at the 10, 25, 50, or 75% application sites. Directive 67/548/EEC, the EU Classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008, and the UN Globally Harmonized System of Classification and Labelling of Chemicals (GHS) guidelines all require a positive response of at least 30% when testing guinea pigs for skin sensitization using an adjuvant type test method. Based on these findings, Rosin, reaction products with formaldehyde was not considered to be a skin sensitizer in guinea pigs.

Rosin oligomers

In a Guinea Pig Maximization Test, 20 female guinea pigs were intradermally injected with Freund's Complete adjuvant, 5% Bevitack 95 (Rosin, oligomers) in Alembicol D, and 5% Bevitack 95 in a 50:50 mixture of Freund's complete adjuvant and Alembicol D (Huntingdon Research Centre Ltd, 1992a). Six days after the intradermal injections, the same interscapular area was clipped and shaved free of hair and the site was pre-treated by gentle rubbing with 0.2 mL per site of 10% sodium lauryl sulphate in petrolatum. The next day 0.4 mL Bevitack 95 (83.3% w/w) in Alembicol D was topically applied and remained in contact with the skin for 48 hours. Two weeks after the induction period, the animals were challenged with two concentrations of Bevitack 95 (83.3% and 41.65%) in Alembicol D. The challenge exposure remained in place for 48 hours under occlusion after which time the patches were removed. The animals were observed for dermal responses at 24, 48, and 72 hours post-challenge. Dermal irritation, characterized as slight erythema, was observed 24 hours after application in control and test substance treated animals exposed to 83.3% Bevitack 95 in Alembicol D. All animals appeared normal after 48 hours. Under the conditions of the study, Bevitack 95 did not demonstrate a potential for dermal sensitization.

The potential of Sylvaros PR 295 (Rosin, oligomers) to produce delayed type hypersensitivity was also investigated in an earlier LLNA study in the mouse (Safepharm Laboratories Limited, 2002a) using test concentrations of 0.5, 5, and 50% w/v in a 4:1 acetone: olive oil vehicle. A stimulation index of 3.0 was recorded for the 50% concentration only. However the result is considered equivocal since the guideline notes that in the event of a borderline positive, the strength of the dose response may be considered. In the case of Sylvaros PR 295, stimulation indices of 1.0 and 1.1 were obtained for the 0.5 and 5% groups, respectively. Thus, no true dose response was present and the results from this LLNA test are considered equivocal.

Resin acids and rosin acids, calcium salts

In a skin sensitization study using the Local Lymph Node Assay, groups of female mice were given daily applications of 5, 10 or 25% (w/v) Resin and rosin acids, calcium salts as a suspension in dimethyl formamide which was applied to the dorsal surface of each ear for 3 consecutive days (Harlan Laboratories Ltd., 2010i). A control group received the vehicle only in the same manner. On Day 5, 3HTdR was injected into the tail vein, the auricular lymph nodes collected 5 hr later, and a single cell suspension prepared. 3HTdR incorporation by the cells was determined, and the Stimulation Index (SI) calculated for each dose of the test substance. A test substance is considered positive for sensitization if the test results produce a threefold or greater increase in the SI. In this study, a SI of less than 3 was recorded for each of the three test concentrations (range of results = 1.44 – 1.47). Based on the results, Resin and rosin acids, calcium salts was not a moderate or strong skin sensitizer in mice, and therefore, lacks a significant potential to cause skin sensitization.

Resin acids and rosin acids, potassium salts

The potential of Resin acids and rosin acids, hydrogenated, potassium salts to produce delayed type hypersensitivity was also investigated in an earlier LLNA study in the mouse (Safepharm Laboratories Limited, 2005a). On this occasion a stimulation index of greater than 3 was recorded in the 25% dose concentration group indicating that the sample should be considered to be a dermal sensitizer according to the interpretative criteria of the protocol. However the reliability of this finding is unclear given the negative LLNA result obtained on another sample of Resin acids and rosin acids, hydrogenated, potassium salts (discussed above) together with the large amount of supporting negative sensitization data available on other members of this category. The result is therefore not taken as evidence that Resin and rosin acids and their salts have a potential to cause skin sensitization.

In a skin sensitization study using the Local Lymph Node Assay, groups of female mice were given daily applications of 5, 10 or 25% (w/v) Resin and rosin acids, potassium salts as a suspension in dimethyl formamide which was applied to the dorsal surface of each ear for 3 consecutive days (Harlan Laboratories Ltd., 2009a). A control group received the vehicle only in the same manner. On Day 5, 3HTdR was injected into the tail vein, the auricular lymph nodes collected 5 hr later, and a single cell suspension prepared. 3HTdR incorporation by the cells was determined, and the Stimulation Index (SI) calculated for each dose of the test substance. A test substance is considered positive for sensitization if the test results produce a threefold or greater increase in the SI. In this study, a SI of less than 3 was recorded for each of the three test concentrations (range of results = 1.06 – 2.38). Based on the results, Resin and rosin acids, potassium salts was not a moderate or strong skin sensitizer in mice, and therefore, lacks a significant potential to cause skin sensitization.

Conclusions

In conclusion, the sensitisation potential of the substances included in this category is well understood and comprises results from three local lymph node assays, twelve Guinea Pig Maximisation Tests and a Buehler test. The results consistently show no evidence of a potential to induce skin sensitisation using methods equivalent or similar to current regulatory guidelines. The conduct and reporting of these studies was GLP-compliant. Positive results obtained in a single Guinea Pig Maximization Test performed using a sample identified as Wood Rosin, (Rosin) (Central Toxicology Laboratory, 1997h) are considered unreliable as the sample submitted for testing was heavily oxidized and degraded. Therefore, the results from this one study are considered erroneous and unrepresentative of the sensitization potential of members of this category. Overall it is concluded that the members of the category Rosins and their salts are not skin sensitisers.


Migrated from Short description of key information:
The sensitisation potential of the substances included in this category is well understood, and reflects information derived from an extensive programme of testing designed to establish whether members of this category possess any potential to induce sensitisation by skin contact. Results are available from tests conducted using local lymph node, Guinea Pig Maximisation and Buehler methods. The results consistently show no evidence of a potential to induce skin sensitisation using methods equivalent or similar to current regulatory guidelines. The conduct and reporting of these studies was GLP-compliant. Positive results obtained in a single Guinea Pig Maximization Test performed using a sample identified as Wood Rosin are unreliable as the sample was heavily oxidized and degraded. The results show clear differences in sensitization potential between native and oxidized rosin, and findings from this study are therefore considered erroneous and unrepresentative of the sensitization potential of members of this category. This is consistent with conclusions reached by the Commission Working Group on the Classification and Labelling of Dangerous Substances (European Commission, 2000) which “agreed to maintain the current Annex I entry of ‘rosin’ unchanged with the classification R43, as declassification, although scientifically justified, would decrease the level of protection within the present regulatory system and the available means of control."

European Commission (2000) Summary Record: Meeting of the Commission Working Group on the Classification and labelling of Dangerous Substances, ECB Ispra, 13-15 October 1999. ECBI/61/99 – Rev. 3, 17.04.00.

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available
Additional information:

Not expected to induce or elicit respiratory sensitization based on an absence of skin sensitization potential

Justification for classification or non-classification

The sensitisation potential of the substances included in this category is well understood and comprises results from tests conducted using local lymph node, Guinea Pig Maximisation and Buehler methods. The results consistently show no evidence of a potential to induce skin sensitisation using methods equivalent or similar to current regulatory guidelines.

Rosin is currently classified for Skin Sensitization according to Annex I to Directive 67/548/EEC as R43: May cause sensitization by skin contact. Rosin is also classified according to EU Classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008. As part of the harmonized translation between Directive 67/548/EEC and EU CLP Regulation (EC) No. 1272/2008, Table 3.1 of EU CLP Regulation (EC) No. 1272/2008 classifies Rosin as “Skin Sensitizer Category 1” and assigns the hazard statement H317: May cause an allergic skin reaction. Table 3.2 of EU CLP Regulation (EC) No. 1272/2008 contains a list of harmonized classifications and labelling of hazardous substances from Annex I to Directive 67/548/EEC. Rosin is assigned the risk phrase R43: May cause sensitization by skin contact in Table 3.2.

  

Subsequent evaluation determined that the single positive study for Rosin was actually conducted with an oxidized form of the test material. Several esters of Rosin have been tested using similar protocols with similar results. When the Rosin esters were heated beyond the specified protocol, the oxidized material caused a positive sensitization response. When those same esters were retested using a different protocol which did not cause oxidation, all sensitization responses were negative. While the oxidized form of Rosin (CAS #100085-68-5) should be considered a skin sensitizer, the recommendation is made to declassify non-oxidized Rosin (CAS # 8050-09-7).