FORMALDEHYDE RISK ASSESSMENT: PROPOSAL OF EXPOSURE LIMITS, CHARACTERISATION OF EXPOSURE, AND DEVELOPMENT OF SCENARIOS.

European Project INDEX-UPRIC 2009 In 2009, DG SANCO funded an update of the 2005 project INDEX “Critical Appraisal of the Setting and Implementation of Indoor Exposure Limits in the EU”. DG SANCO required a particular focus on formaldehyde, on the basis of new papers published following its re-classification in Group 1 (sufficient epidemiological and scientific evidence for an association with nasopharyngeal cancer) by IARC. INDEX-UPRIC 2009 (“UPdate of PRIority Compounds”) aimed at reviewing recent scientific data, but also at re-examining previous studies and re-considering the reference values proposed in 2005. From selected results of scientific literature and an innovative approach in applying uncertainty factors, making the best use of chemical specific data on toxicodynamics and toxicokinetics, new reference limits have been proposed for exposure to formaldehyde in indoor settings. The reference range of values for short-term exposure (30 minutes) proposed at EU level is 70-100 ppb (or 90-120 µg/m3); it is comparable to most of exposure limits set by other national or international organisation. WHO in particular, in the latest version of IAQ guidelines (just published in December 2010), even if resulting from a different calculation, recommends a limit of 100 µg/m3 (~80 ppb) for short-term exposure. The reference values proposed by INDEX UPRIC 2009 should be used for the risk characterisation of situations related to acute exposure to formaldehyde indoors. In the light of scientific data available, it can be considered protective from carcinogenic effects in relation to short-term exposure, although it is derived from an irritation endpoint. Always looking at the scientific evidence available so far, there is no indication of cumulative effects following exposure to low concentrations (below 1 ppm), as adverse effects seem to recover shortly after exposure period. Current knowledge allows to reasonably assume that the proposed reference range of concentrations is also protective from long-term health effects due to repetitive short-term exposures. However, attention must be paid at the outcomes of genotoxicity studies (currently inconclusive), particularly with concern to a potential association of formaldehyde with increased incidence of tumours other than those located in the site of exposure (airways tissues). Exposure characterisation and Exposure Scenarios in hospitals The hazard characterisation of formaldehyde carried out in INDEX UPRIC project indicates that recurrent, short-term, peak exposures, rather than exposure to constant levels, are expected to adversely affect eyes and upper airways in exposed subjects, posing also a potential risk for more severe health outcomes. Exposure to formaldehyde in occupational settings, and particularly in Pathology labs, appears to be characterised by concentration fluctuations and peaks. To perform a correct exposure assessment in Pathology Units, and to eventually associate exposure levels with health effects, an in-depth understanding of determinant factors of exposure and actual air levels, is a requirement. The project aimed to reach this goal through the development of detailed Exposure Scenarios and the characterisation of concentration fluctuations during specific tasks in Pathology Units of two different hospitals. Three monitoring methods have been adopted: passive, active and in-continuous techniques have been tested and their outcomes analysed. Potential hazards for operators’ health have been identified during the performance of several tasks, being measured formaldehyde levels clearly above the TLV-C set by US ACGIH (0.3 ppm). From circumstances observed during monitoring, some misuses have been identified as well as inappropriateness of some organisational, logistic, and mitigation factors leading to high level of exposure (even above 1 ppm). Exposure Scenarios for critical tasks have been presented, including operational conditions, formaldehyde levels detected by the three techniques, possible causes of rises above the TLV-C, and proposed RMMs . Due to intrinsic properties of formaldehyde, its release from formalin solution is unavoidable, thus the implementation of RMMs is particularly crucial to avoid excessive exposure of operators. Much can be done in order to reduce critical situations, but measures to put into practice must be shared within all personnel working in the Unit. Less problematic alternatives (i.e. glutaraldehyde) should be also taken into account, considering the current debate on carcinogenicity and being formaldehyde in revision of classification at EU level as a consequence of a French request to place it among Carcinogens Category 1. Proposed RMMs have started to be put into place by Prevention and Protection Service of both hospitals. Very soon after their implementation another monitoring survey is foreseen, in order to check their effectiveness and appropriateness.