Dimethyl fumarate: ANSES update on available knowledge

Following these events, the marketing of items containing DMFu was temporarily suspended in France in December 2008. This ban was extended for a 1-year period in March 2009 by a renewable European Commission Decision(1). At the same time, France proposed a process to restrict DMFu under the European REACh regulation. The aim of this process is to permanently ban the use of DMFu and the marketing of items containing it (2) in Europe. The European Commission is expected to issue a Decision by the end of 2011 or the very beginning of 2012.

The aim of these measures is to prevent the onset of new cases by keeping items containing DMFu from entering the market. However, although the number of reported cases has considerably decreased, more than one hundred cases involving suspected exposure to DMFu were reported to poison control and toxicant monitoring centres between January 2009 and February 2010. Moreover, even though items containing or suspected of containing DMFu had been removed from their homes, several people reported persistent health problems.
Lastly, on a broader level, the case of DMFu raises questions regarding the regulatory framework applicable in Europe to prevent worker and/or consumer exposure to substances used in certain regions of the world to protect consumer products or treat transport containers, and the plan that should be adopted to monitor potential adverse effects linked to this exposure.

The Agency's work

In this context, the Agency was requested in 2009 to undertake emergency measurement campaigns to assess DMFu remaining in the homes of people who had been exposed in the past and were complaining of persistent health problems. The results of these investigations were published in December 2009 and January 2010 and show that residual DMFu can be found in textiles that are a priori absorbent and have been in direct contact with (throws, cushions, etc.), or in the immediate environment of (curtains, etc.) a contaminated item.
In tandem with these investigations, the Agency was also requested to compile and expand the available data on DMFu and similar substances for which knowledge in terms of physico-chemical and toxicological properties was then deficient.

To undertake its expert assessment, the Agency researched and analysed the available bibliographic data and supplementary data collected via specific interviews and studies that had been entrusted to some of the Agency's partners (CSTB(3), InVS-CCTV(4), AFSSAPS(5), Paris Sud University).

Exposure sources

The Agency sought to compile an exhaustive list of sectors that use DMFu or whose products are contaminated with this substance, in order to precisely determine all potential sources of exposure to DMFu for workers and consumers. This work confirmed that DMFu is only found in consumer products when it has been used by manufacturers for its fungicidal properties to protect, during transport and storage, various imported products (clothing, products made with leather, PVC (polyvinyl chloride) or polyurethane, and upholstery products, mainly those made of leather). Items treated with or contaminated by DMFu are therefore the main source of exposure to DMFu in general and

occupational environments in France.
Apart from treated items, in light of its physico-chemical properties and particularly its volatile character, DMFu is likely to be found:

• in materials that have been in contact with or close to a contaminated item, through secondary contamination;
• in the air, through volatilisation from a primary source;
• in dust (secondary contamination);
• on the surface of elements, on the floor or indoor surfaces (secondary contamination).

Health effects

Regarding the toxic effects of DMFu and similar substances, the work undertaken by ANSES confirms the irritating and/or sensitising potential of DMFu which can therefore cause irritative or allergic contact dermatitis. Some similar substances may also have sensitising potential.

ANSES also sought to determine whether effects other than irritative or allergic contact dermatitis were likely to be observed after exposure through inhalation or skin contact with residual DMFu (secondary contamination).

To do so, ANSES compared, in the framework of a worst-case exposure scenario(6), the available data related to residual or secondary DMFu contamination in the air or on surfaces with knowledge related to the toxicity of DMFu.

On this basis, there are no expected systemic health effects (carcinogenic or other) that are likely to occur after exposure to residual DMFu from inhalation or skin contact. Regarding local effects on the respiratory tract, the available data remain limited and do not confirm that DMFu is toxic when inhaled.

To improve knowledge of this substance and prevent the onset of new cases, ANSES is issuing a series of recommendations aiming to improve the characterisation of risks related to this substance, monitor potential substitutes for DMFu, and protect and monitor workers potentially exposed to this substance (implementation of appropriate protective equipment, medical surveillance of potentially exposed personnel).

(1) The ban is valid for all items that contain more than 0.1 mg/kg of DMFu.
(2) in quantities greater than 0.1 mg/kg
(3) French Scientific and Technical Centre for Building
(4) French Institute for Public Health Surveillance - committee for the coordination of toxicant monitoring
(5) French Health Products Safety Agency
(6) That is, considering systematic exposure at the maximum concentration levels and in conditions that undoubtedly overestimate actual exposure (exposure period, contact surface, etc.).