This Opinion has been adopted during the SCCS 15th plenary meeting, on 26 and 27 June, 2012.

To question 1 : "Based on the current knowledge on the chemistry, biology and toxicology of methylene glycol, should methylene glycol be considered equivalent to formaldehyde?", SCCS answers:

Although formaldehyde and methylene glycol are different molecules from a scientific chemical point of view, there is a close interrelationship of  formaldehyde and methylene glycol in aqueous solution and a rapid mutual conversion in a dynamic equilibrium. Therefore, from a practical point of view, it is justified to consider the aqueous mixture of gaseous formaldehyde and methylene glycol as “free formaldehyde” and the quantities as “formaldehyde equivalents” (preferably expressed as formaldehyde concentration) in aqueous solutions. The term “formaldehyde equivalents” adequately describes the fact that methylene glycol is continuously converted to gaseous formaldehyde in aqueous solution, and vice versa, at any equilibrium, which can be easily shifted by heating, drying, and any other conditions that increase or decrease the amount of gaseous formaldehyde.
Therefore, the SCCS, in line with the position of other bodies and panels (American Chemical Council 2010, CIR 2012, OSHA 2010, considers methylene glycol as a formaldehyde equivalent.

To question 2 : "If …