EU court overturns coal tar chemical’s aquatic toxicity classification

The subscription news service Chemical Watch reports that the European General Court has overturned the classification of coal tar pitch as a “substance with category 1 acute and chronic aquatic toxicity,” finding that the European Commission had committed a “manifest error of assessment” in adopting a regulation that classified coal tar pitch on the basis of the physicochemical characteristics of individual PAHs that may be present as constituents of coal tar pitch rather than on the physicochemical characteristics of the whole mixture of coal tar pitch itself.

As reported by Chemical Watch,

…18 companies appealed against the aquatic toxicity classification. One of their arguments was that the Commission had displayed a “manifest error of assessment” in classifying CTPHT on the basis of its constituents.

The court agreed, saying the Commission failed to comply with its obligation to take into consideration all the relevant factors and circumstances, so as to take due account of the proportion in which the 16 constituents are present in CTPHT and their chemical effects.

In its written opinion, which is available here, the Court noted the very low solubility of coal tar pitch in water, which is in contrast with the assumption made by European Chemical Agency’s (ECHA’s) Risk Assessment Committee (RAC) that all of the individual PAHs dissolved in water and were therefore available to aquatic biota. According to the Court’s opinion, the highest tested actual solubility of coal tar pitch was 0.0014%, but the European Commission accepted ECHA’s individual PAH constituent method as the basis of the “category 1 acute and chronic aquatic toxicity” classification. The PAH constituent method resulted in a calculated solubility of 9.2%. The Court concluded

…such a value is not realistic, given that the maximum rate is 0.0014%.

According to Chemical Watch, the Court’s ruling is a landmark case in the EU because, apparently for the first time, it sets limits on the discretionary powers of EU government agencies when assessing chemical risks.

The ruling is also relevant in the United States.  In its attempts to scare the public about coal tar, the USGS has used a similar approach by ignoring information about how real world coal tar-derived mixtures behave in the environment, relying instead on adding up theoretical toxicities based on individual PAHs similar to the overturned ECHA method.

The ECHA method is also similar to the US Environmental Protection Agency’s Relative Potency Factor (RPF) method of calculating theoretical risks of substances that contain a mixture of PAHs. EPA’s Science Advisory Board (SAB) conducted a peer review of the RPF approach to assessing the toxicity of PAH-containing substances in 2010. PCTC joined with 5 other trade associations to submit technical comments on the documents under review. Those comments are available here. As a result of the SAB’s review, EPA is in the process of substantially revising its approach to PAH mixtures. EPA intends to submit the revised PAH mixtures document to the SAB for another round of review. EPA’s schedule for that document is available on its web site, here.

A more in-depth discussion of EPA’s RPF approach to PAH assessment is available here.





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