Scope Document for TSCA Evaluation of PV29 Has Range of Endpoints

The US EPA will consider a range of human health and environmental hazard endpoints in its forthcoming TSCA risk evaluation of Pigment Violet 29 (PV29). But it has ruled out further consideration of genotoxicity and carcinogenicity.

The pigment is one of ten substances in the first tranche of chemicals to be evaluated under the new TSCA. The agency issued scope documents for each on 23 June. Industry will scrutinise these to see how EPA intends to implement the early stages and the sort of uses, exposures and endpoints that are included.

In the case of PV29, human health hazard endpoints for consideration include: acute toxicity; eye irritation; skin irritation; skin sensitisation; repeated-dose toxicity; and reproductive and developmental toxicity. The agency says it has previously identified all of these.

In contrast, in vitro genotoxicity tests have given negative results, without metabolic activation. Furthermore, structure-activity evaluation suggests there is "negligible potential" for the "unusual" molecule - comprising a 2D aromatic network of seven rings - to intercalate into DNA, the agency said.

Although carcinogenicity tests have not been conducted, the agency says, the pigment is unlikely to be carcinogenic because of the negative genotoxicity results and structure-activity considerations, as well as the expectation of negligible absorption and uptake, based on its "very low" solubility.

The environmental hazard endpoints for consideration are acute and chronic toxicity for aquatic and terrestrial organisms. The agency expects PV29 to be highly persistent in the environment but have low bioaccumulation potential.

Data sources

The scoping document discusses three potential sources of hazard information: the EU REACH registration dossier for PV29, a 2017 letter to the EPA from the Colour Pigment Manufacturers Association (CPMA), and scientific literature.

Summary information from the REACH dossier is freely available via Echa’s registered substances database but the full study reports are not.

This information shows that the dossier contains data for a wide range of human health and environmental hazard endpoints. In all cases, the returned results are negative. Correspondingly the registrants have not submitted any hazard classification notifications under CLP.

The EPA says that it is trying to acquire the full study reports. To do so, it will need the cooperation of either Echa or the two REACH registrants for the substance: BASF Colours & Effects and Sun Chemicals.

But David Wawer at CPMA points out that there are legal barriers preventing the companies - both association members - from offering these to the EPA. The regulatory and legal structure for creating REACH Siefs - the mandatory substance information exchange fora that registrants must join to enable data sharing - has no relationship to what goes on in North America.

How the EPA will handle intellectual property rights and confidentiality claims under TSCA remains a hot topic of debate. One lawyer has said that the agency’s current plans would be a disaster for data owners.

Mr Wawer suggests the agency could "take it on the word of their European and Canadian counterparts … One would think that the robust summaries - which they cite - are adequate".

Conditions of use

The scoping document gives four "primary" industrial and commercial uses, as well as one consumer use. These are:

as an intermediate to create or adjust other perylene pigments;
incorporation into paints and coatings used primarily in the automobile industry;
incorporation into plastic and rubber products used primarily in automobiles and industrial carpeting;
in merchant ink for commercial printing; and
in consumer watercolours and acrylic paint.
The document says 90% of the PV29 produced in the US is processed as a site-limited intermediate in the formation of other perylene pigments or "used to incorporate into formulation, mixture or reaction products".

There was not time for public consultation on a scoping document draft, the EPA says. But the agency will take public comments on a ‘problem formulation document’, which will refine the scope - "as an additional interim step" - before publication of the draft risk assessment.

The agency expects to publish the problem formulation document within six months.The US EPA will consider a range of human health and environmental hazard endpoints in its forthcoming TSCA risk evaluation of Pigment Violet 29 (PV29). But it has ruled out further consideration of genotoxicity and carcinogenicity.

The pigment is one of ten substances in the first tranche of chemicals to be evaluated under the new TSCA. The agency issued scope documents for each on 23 June. Industry will scrutinise these to see how EPA intends to implement the early stages and the sort of uses, exposures and endpoints that are included.

In the case of PV29, human health hazard endpoints for consideration include: acute toxicity; eye irritation; skin irritation; skin sensitisation; repeated-dose toxicity; and reproductive and developmental toxicity. The agency says it has previously identified all of these.

In contrast, in vitro genotoxicity tests have given negative results, without metabolic activation. Furthermore, structure-activity evaluation suggests there is "negligible potential" for the "unusual" molecule - comprising a 2D aromatic network of seven rings - to intercalate into DNA, the agency said.

Although carcinogenicity tests have not been conducted, the agency says, the pigment is unlikely to be carcinogenic because of the negative genotoxicity results and structure-activity considerations, as well as the expectation of negligible absorption and uptake, based on its "very low" solubility.

The environmental hazard endpoints for consideration are acute and chronic toxicity for aquatic and terrestrial organisms. The agency expects PV29 to be highly persistent in the environment but have low bioaccumulation potential.

Data sources

The scoping document discusses three potential sources of hazard information: the EU REACH registration dossier for PV29, a 2017 letter to the EPA from the Colour Pigment Manufacturers Association (CPMA), and scientific literature.

Summary information from the REACH dossier is freely available via Echa’s registered substances database but the full study reports are not.

This information shows that the dossier contains data for a wide range of human health and environmental hazard endpoints. In all cases, the returned results are negative. Correspondingly the registrants have not submitted any hazard classification notifications under CLP.

The EPA says that it is trying to acquire the full study reports. To do so, it will need the cooperation of either Echa or the two REACH registrants for the substance: BASF Colours & Effects and Sun Chemicals.

But David Wawer at CPMA points out that there are legal barriers preventing the companies - both association members - from offering these to the EPA. The regulatory and legal structure for creating REACH Siefs - the mandatory substance information exchange fora that registrants must join to enable data sharing - has no relationship to what goes on in North America.

How the EPA will handle intellectual property rights and confidentiality claims under TSCA remains a hot topic of debate. One lawyer has said that the agency’s current plans would be a disaster for data owners.

Mr Wawer suggests the agency could "take it on the word of their European and Canadian counterparts … One would think that the robust summaries - which they cite - are adequate".

Conditions of use

The scoping document gives four "primary" industrial and commercial uses, as well as one consumer use. These are:

as an intermediate to create or adjust other perylene pigments;
incorporation into paints and coatings used primarily in the automobile industry;
incorporation into plastic and rubber products used primarily in automobiles and industrial carpeting;
in merchant ink for commercial printing; and
in consumer watercolours and acrylic paint.
The document says 90% of the PV29 produced in the US is processed as a site-limited intermediate in the formation of other perylene pigments or "used to incorporate into formulation, mixture or reaction products".

There was not time for public consultation on a scoping document draft, the EPA says. But the agency will take public comments on a ‘problem formulation document’, which will refine the scope - "as an additional interim step" - before publication of the draft risk assessment.

The agency expects to publish the problem formulation document within six months.