A most interesting study concerning the severity of eye effects caused by accidental exposure to detergent and cleaning product has recently been published by Scazzola et al., 2019. The study investigated the predictivity of a product’s classification for eye hazard following reported accidental human exposures to common household detergent and cleaning products. In contrast to the eye hazard classification suggested by the EU’s CLP calculation method, the vast majority of eye exposures reported to various EU Poison Control Centres caused only minor or no symptoms. With a view to the CLP mixture classification rules, the authors concluded that deriving eye hazard classifications for this product category using all available physico-chemical and toxicological information on the product and its ingredients itself or on similar mixtures is a much better predictor of medically relevant symptoms than the EU CLP calculation method.
The primary basis for the classification of mixtures for eye hazard under the EU CLP Regulation is based on actual data on the mixture itself. This could include in vivo data according to OECD TG 405, validated in vitro methodologies, epidemiological data and/or human experience from accidents or in-market surveillance. If data on the mixture itself is not available, data on similar mixtures can be used by either applying the bridging principles or in a weight-of-evidence approach in consideration of all available information. If no conclusive expert classification can be derived, the EU CLP calculation method, originally introduced by UN GHS, must be applied. Due to its simplicity, the calculation method is often applied by small- and medium-size manufacturers who typically do not have the toxicological resources, know-how and databases.
The application of the calculation method for the determination of eye hazards resulted in an increased number of classifications of detergent and cleaning products in the highest eye hazard category (‘Eye Cat. 1’). This is because of the products’ surfactant content and the lowering of the cut-off levels of mixtures containing Eye Cat. 1 classified substances from 10% in the former DPD to 3% in CLP. An Eye Cat. 1 classification goes along with the requirement to put a corrosive pictogramme and the signal word ‘Danger’ on the label. As a result of the CLP rules, most daily use detergents would be labelled identically to caustic or highly acidic specialty cleaners. This suggests to the consumer that both product types have the same hazards. In the long run, the consumer cannot make this distinction anymore, which will ultimately lead to a devaluation of the product label. It goes without saying that product hazards must be correctly identified to ensure sustained safe use. But over-classification should be equally avoided to ensure consumers continue to read and follow label instructions.
The Scazzola et al. (2019) study has to be seen in this context. It investigated the predictivity of consumer products’ classification for eye hazard, following reported accidental human exposures to common household and cleaning products against the hazard classification approaches included in the EU CLP Regulation. The investigators concluded that derivation of an eye hazard classification based on all available data and information was much more predictive of medically relevant symptoms than the EU CLP calculation method. The latter led to a poorer differentiation between irritating products versus products potentially causing serious eye damage. The underlying human dataset for the assessment were obtained from a prospective multicentre poison centre study that medically followed-up reported eye effects caused by accidental exposures to detergents and cleaning products (Hermanns-Clausen et al., 2015; Hermanns-Clausen et al., 2019). The authors of the so-called MAGAM II study concluded that most patients only experienced minor symptoms and that serious eye damage, defined as long-lasting, potentially irreversible symptoms, only occurred very rarely after accidental ocular exposures to detergents or cleaning products. However, the investigators of the MAGAM II study stated also that eye irrigation immediately after exposure may have been a mitigating factor, preventing more severe effects.