The life cycle of solvents is a significant part of our operational and supply chain footprint.

Solvents play a key role in the synthesis of our compounds, the formulation of final products and the cleaning of equipment. Solvents are the primary component that we must control in our emissions, effluents and wastes. Because of their significance, we have a strong focus on green chemistry and are targeting solvent-use reductions instead of setting a hazardous-waste reduction goal.

We have an active green chemistry program to design our processes to use less solvents and to reuse and recycle solvents. But when the recovery and reuse of regenerated solvents aren’t practical, we try to find other beneficial uses for our spent solvents. We also employ in-process and end-of-pipe treatment technologies and controls to reduce our solvent emissions. We seek to use water-based methods for equipment cleaning when they are equally effective.

In 2011, Merck used more than 85 million kilograms of solvent in production and cleaning processes. The increase in solvent use in 2010 was due in large part to the purchase of a large manufacturing facility in Pennsylvania. The recent decrease is related to more facility closures and more processes being shut down than were added over the year. In 2011, more than one-third of the solvents we used for manufacturing products and cleaning equipment were recovered solvents.