Occupational exposure limits for chemical agents

Expert appraisal necessary for defining occupational exposure limits for chemicals

Since 2005, the Agency has been responsible for organising the independent, multidisciplinary, collective scientific expert appraisal needed for setting occupational exposure limits (OELs). A dedicated expert committee has therefore been set up to support the Agency in this mission. At the same time, ANSES is also responsible for drafting a list of chemicals for priority assessment, which it proposes to the French Ministry of Labour, thus enabling the Ministry to develop the programme for the OEL expert mission after consultation with the social partners.

Prevention of chemical risk in the workplace is primarily based on the principle of substitution (replacing a hazardous product with a harmless or less harmful product) or failing that, reducing the concentration of pollutants to the lowest levels possible. For many hazardous chemicals, it is still necessary to protect workers’ health by establishing concentration levels of pollutants in the workplace atmosphere that must not be exceeded during a reference period, along with biological limit values. The Ministry of Labour is thus statutorily responsible for setting occupational exposure limits (OELs) and biological limit values (BLVs). These values can be binding if they are fixed by decree, or indicative if they are fixed by ministerial order. They are an important tool for reducing chemical risk in the workplace. 

In this context and as part of the first Occupational Health Plan, in 2005 the Agency was asked by the Ministry of Labour to organise the phase of independent, collective scientific expert appraisal needed for setting OELs based on health criteria.

The purpose of the scientific expert phase entrusted to ANSES is to recommend not only concentration levels (atmospheric and biological) relevant to protecting worker health, but also measurement methods for comparing occupational exposures with the recommended OELs. 

As part of its commitment to making its expertise work more socially representative, at the end of 2012 ANSES established two types of calls for contributions – prior and subsequent to its work – that are intended to enrich and shed light on the scientific process by which these values are established. In this way, the Agency is also responding to the wishes of its occupational health thematic steering committee.

How ANSES works 

The occupational exposure limits (OELs) recommended by ANSES are air concentrations of a chemical that almost all workers can breathe during a specified period without any known risk to health at the time of the expert appraisal. Levels are determined on the assumption that the population of exposed workers is homogeneous, and includes neither children nor the elderly. 

Concentration levels are determined based on scientific data from human studies (epidemiological and clinical studies) or experimental animal studies (toxicological studies). 

When considered appropriate, in addition to the atmospheric OELs, ANSES states its position on information that may be useful for implementing biological monitoring of exposure by occupational physicians: this involves recommending the determination of certain biological parameters, preferably in urine but also sometimes in blood or exhaled air, depending on the substance. All exposure routes and certain factors interfering with absorption (such as ventilator flow rate) are taken into account when recommending biological limit values (BLVs) and/or biological reference values (BRVs).

Results and recommendations

Under the 2005-2009 occupational health plan (PST1), the Agency was asked in the first instance to conduct scientific expert appraisals for the following substances: toluene; formaldehyde; 2-butoxyethanol; 2-butoxy acetate (or 2-butoxyethanol acetate); dichloromethane; trichloroethylene; refractory ceramic fibres; asbestos fibres; styrene; styrene oxide; perchloroethylene (or tetrachloroethylene); acrylamide, cadmium and its compounds; hexavalent chromium compounds; 1,3-butadiene; cobalt and its compounds; carbon monoxide; di-2-ethylhexylphthalate (DEHP); benzyl butyl phthalate (BBP); di-n-butyl phthalate (DBP); beryllium; benzo[a]pyrene; dust without specific effects. 

On 3 February 2012, ANSES received a formal request from the Ministry of Labour to conduct the scientific expert appraisal phase for the following agents: benzene, ethanol, endotoxins, octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), hexamethylene diisocyanate (HDI), toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), isophorone diisocyanate (IPDI), butanol, crystalline silica and polycyclic aromatic hydrocarbons, in addition to an expert appraisal for biological monitoring of 1PG2ME and its acetate; and an expert appraisal with a view to setting a minimum oxygen level. 

On 11 March 2013, ANSES received a formal request from the Ministry of Labour to give priority to the scientific appraisal for revision of the occupational exposure limit value (OEL) and biological limit value (BLV) for lead and its compounds. It was also requested to proceed to a comparative analysis of regulations in force on this subject in the other countries of the European Union.

On 18 November 2015, ANSES received a formal request from the Ministry of Labour to give priority to  the scientific appraisal for revision of the occupational exposure limit value (OEL) for dust without specific effects.

Since it was entrusted with this mission, the Agency has submitted several recommendations for atmospheric occupational exposure limits and biological limit values along with methodology reports. It has also conducted an expert appraisal on the assessment of measurement methods for eighteen substances in the context of the transposition into French law of the European regulations (Directive 2009/161/EU). 

OELs: Coordination between French and European levels

At European level, a scientific expert committee (the SCOEL) is in charge of recommending OELs, on which the European Commission relies when issuing directives setting EU-wide OELs. 

The documents drafted by the SCOEL go through a phase of consultation with the Member States and stakeholders, during which comments or additional scientific information can be submitted.

ANSES is one of the identified focal points in France for scientific expertise of the SCOEL’s recommendations. As such, it is consulted for a critical reading and to state its position on the relevance of the values recommended by this committee. In an attempt to pool resources and expertise, and unless there is fundamental disagreement, substances recently appraised at European level do not then undergo specific expert appraisal at the national level with regard to their health effects. However, the assessment of methods for measuring pollutants in the workplace remains the responsibility of the OEL Committee, since the SCOEL does not typically address this point.