Expertise en vue de la fixation de valeurs limites d’exposition à des agents chimiques en milieu professionnel - Évaluation des effets sur la santé pour le dioxyde de titane sous forme nanométrique (nTiO2, P25) CAS N° 13463-67-7: Avis de l’AnsesRapport d’expertise collective

The French system for establishing Occupational Exposure Limits OELVs has three clearly distinct phases: - Independent scientific expertise (the only phase entrusted to Anses); - Proposal by the Ministry of Labour of a draft regulation for the establishment of limit values, which may be binding or indicative; - Stakeholder consultation during the presentation of the draft regulation to the French Steering Committee on Working Conditions (COCT). The aim of this phase is to discuss the effectiveness of the limit values and if necessary to determine a possible implementation timetable, depending on any technical and economic feasibility. The organisation of the scientific expertise phase required for the establishment of Occupational Exposure Limits (OELVs) was entrusted to the agency in the framework of the French 2005-2009 Occupational Health Plan (PST). In 2015, Anses submitted a proposal of classification to the European Chemicals Agency (ECHA) for the carcinogenicity by inhalation of TiO2 (carcinogenic category 1B) under European Regulation (CLP) No 1272/2008 on the classification, labelling and packaging of dangerous substances and mixtures. In 2017, ECHA's Risk Assessment Committee (RAC) concluded that TiO2 in all its forms should be classified as a suspected human carcinogen of category 2 by inhalation. Anses was requested by the Directorate General for Health (DGS), Directorate General for Risk Prevention (DGPR) and Directorate General for Labour (DGT) on 4 July 2017 to establish a chronic TRV by inhalation for TiO2 under nanoform. This request under the terms of the referral is the result of “the analysis of the R-Nano database indicating that many industrial sites in France use titanium dioxide under nanoform. These uses can lead to exposure of workers but also to exposure of populations via off-site emissions”. The referral notes that “the International Agency for Research on Cancer (IARC) has classified titanium dioxide as respirable particles as a possible carcinogen by inhalation”. An opinion was published in April 2019 defining a TRV applicable only to Aeroxide TiO2 P25 of 0.12 µg/m3 , with a confidence level moderate (Anses, 2019). Following this work, and in accordance with the corresponding protocol of agreement, Anses launched the work for the establishment of OELs. In addition, under the REACh regulation, Anses is currently examining a dossier for assessing the hazards and risks of TiO2 to human health and the environment. As part of the examination of this dossier, additional data on the hazards and uses of TiO2 may be required by Anses from industry. The OELs, as proposed by the “Health reference values” Committee (HRV Committee), are concentration levels of pollutants in workplace atmospheres that should not be exceeded over a determined reference period and below which the risk of impaired health is considered as negligible. Although reversible physiological changes are sometimes tolerated, no organic or functional damage of an irreversible or prolonged nature is accepted at this level of exposure for the large majority of workers. These concentration levels are determined by considering that the exposed population (the workers) is one that excludes both children and the elderly. These concentration levels are determined by the HRV Committee experts based on information available from epidemiological, clinical and animal toxicology studies. Identifying concentrations that are safe for human health are the results of correction factors applied to the values identified directly by the studies. These corrections factors take into account a number of uncertainties inherent to the extrapolation process conducted as part of an assessment of the health effects of chemicals on humans. The Committee recommends the use of three types of values: - 8-hour occupational exposure limit (8h-OEL): this corresponds to the limit of the timeweighted average (TWA) of the concentration of a chemical in the worker's breathing zone over the course of an 8-hour work shift. In the current state of scientific knowledge (toxicology, medicine and epidemiology), the 8h-OEL is designed to protect workers exposed regularly and for the duration of their working life from the medium- and long-term health effects of the chemical in question; - Short-term exposure limit (STEL): this corresponds to the limit of the time-weighted average (TWA) of the concentration of a chemical in the worker's breathing zone over a 15-minute reference period during the peak of exposure, irrespective of its duration. It aims to protect workers from adverse health effects (immediate or short-term toxic effects such as irritation phenomena) due to peaks of exposure; - Ceiling value: this is the limit of the concentration of a chemical in the worker's breathing zone that should not be exceeded at any time during the working period. This value is recommended for substances known to be highly irritating or corrosive or likely to cause serious potentially irreversible effects after a very short period of exposure. These three types of values are expressed: - in mg.m-3, i.e. in milligrams of chemical per cubic metre of air, or in ppm (parts per million), i.e. in cubic centimetres of chemical per cubic metre of air, for gases and vapours; - or in mg.m-3 only for liquid (fog) and solid (fumes) aerosols; - or in f.cm-3, i.e. in fibres per cubic centimetre for fibrous materials. The 8h-OELV may be exceeded for short periods during the working day provided that: - the weighted average of levels calculated over the entire working day is not exceeded; - the short term exposure limit value (STELV), when one exists, is not exceeded. In addition to the OELs, the HRV Committee assesses the need to assign a “skin” notation, when significant penetration through the skin is possible. This notation indicates the need to consider the dermal route of exposure in the exposure assessment and, where necessary, to implement appropriate preventive measures (such as wearing protective gloves). Skin penetration of substances is not taken into account when determining the atmospheric limit levels, even it can potentially cause health effects even when the atmospheric levels are respected. The HRV Committee assesses the need to assign a “noise” notation indicating a risk of hearing impairment in the event of co-exposure to noise and the substance below the recommended OELs, to enable preventionists to implement appropriate measures (collective, individual and/or medical) (Anses 2017). The HRV Committee also assesses the applicable reference methods for the measurement of exposure levels in the workplace. The quality of these methods and their applicability to the measurement of exposure levels for comparison with an OEL are assessed, particularly with regards to their compliance with the performance requirements in the NF-EN 482 Standard and their level of validation12. Once they have been assessed, these methods can be classified into one of the following categories: - Category 1A: the method has been recognized and validated (all of the performance criteria in the NF-EN 482 Standard are met); - Category 1B: the method has been partially validated (the essential performance criteria in the NF-EN 482 Standard are met); - Category 2: the method is indicative (essential criteria for validation are not clear enough); - Category 3: the method is not recommended (essential criteria for validation are lacking or inappropriate) (Anses, 2017).

Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.