Here is the email response I received from Merrell:

We recognize the concerns associated with leaching chemicals that are
applied all too frequently in consumer products. That is why we do not treat
our shoes with leachate chemical antimicrobials. When we researched
antimicrobial features we went through the tool box and saw the same
problems you know of with chemical antimicrobials. They bleed off, can get
into the environment, and have who knows what kind of effect in the
landfill. At the same time we want to offer the best shoe possible and that
includes shoes that stay cleaner and last longer.

Even for that goal though we would not compromise, or use chemical leachates
like you find in lesser footwear. As such our “antimicrobial” technology is
quite unique and different from the norm. In fact, in some ways it is known
better for what it doesn’t have:

It contains:
NO Triclosan
NO Silver
NO Tin
NO Heavy metals
NO Bis-chlorinated phenols
NO Halogenated compounds
NO Chemical mode of action

So what does our technology end up using.
.Sand.

Yep that’s right, we have included into our lining a polymer structure that
starts out life as basic quartz. It may sound simple because it is. Instead
of bleeding chemicals and hazardous reactions we have used Aegis technology
to bind this polymer into the lining which makes the surface a place that
stays cleaner during use and helps your shoes last longer. There are no
chemical reactions and no chemical release. Just a protected surface for
longer lasting footwear.

I hope this helps give some insight into our design process, and I want to
thank you for using our Merrell products.
We realize you have a choice when it comes to footwear and we plan to
continue to provide you the best products with both you and our environment
in mind.

Thank you,

Zach Weyerman
Merrell Consumer Accounts Specialist U.S.
T 1.800.288.3124 F 1.888.306.0936
http://www.merrell.com