Risk assessment of DMFu residues in dwellings following contamination by treated furnitures

In recent years, numerous patients in Europe were reported to suffer from dimethyl fumarate (DMFu)-induced dermatitis, following contact with DMFu contaminated articles. DMFu was used as a biocide preventing mould development though it was not registered as a biocide in Europe. In France, from October 2008 to 2009, more than 100 cases were reported and despite ban of all DMFu-containing articles and removal of potentially contaminated products, some people leaving in a house where a DMFu contaminated article was present for some time were still reporting health problems. The French Agency for Food, Environmental and Occupational Health and Safety (Anses) was thus mandated to assess whether the past presence of DMFu contaminated articles in a dwelling could pose a threat to the health of its inhabitants. A risk assessment was performed based on the classical risk analysis approach for environmental contaminants. Hazard assessment of DMFu in relation to sensitising properties was performed based on human case reports collected in France between January 2009 and February 2010 and an experimental LLNA study on mice. For around half of the 132 individual cases reported, the causal link to DMFu was considered at least probable. An LLNA study following OECD guideline clearly showed a strong sensitizing potential of DMFu with an EC3 of 0.21%. Exposure was assessed by measuring DMFu in items sampled in pre-selected dwellings. It demonstrated that DMFu exposure can persist after removal of primary contaminated items. It was assumed that sofas which possibly contained DMFu and which had been removed from the households could be the source of secondary contamination. Based on a NOAEL of 0.0001%, it was concluded that there was clearly a risk of skin reactions in patients previously sensitized to DMFu; an irritant response was unlikely. It was also considered that significant health effects through the respiratory route are not supported by available data.