From Fibre2Fashion.com:

Dimethylfumarate (DMF) is a biocide used to prevent mould growth that can cause deterioration of leather furniture or footwear during storage or transport, especially in a humid climate. DMF is often contained in pouches fixed inside furniture or added to footwear boxes, where it sublimates protecting product from mould. Often, the pouches look similar to those used to contain silica gel, a non-harmful desiccant frequently used in leather products.

In France, Poland, Finland, Sweden and the UK, consumers have experienced skin irritation, redness and burns and, in some severe cases, acute respiratory difficulty, which is said to have been caused by DMF contact with skin.

European Directive (2009/251/EC) was published on the 17th March 2009 and requires that products containing DMF are not placed on the market: this means the presence of DMF in one or more pouches or in a concentration greater than 0.1 mg/kg of the weight of the product or part of the product. The Directive also requires any product containing DMF that has already been placed on the market be withdrawn by the 1st May 2009 and consumers to be made aware of the potential risks.

For more information, click on the above link.

Relevant Nexreg Compliance Links: Nexreg, REACH Compliance, EU SDS Authoring.