This was on the Olfa FAQ--
"Due to production and distribution, a new OLFA rotary mat can emit an odorous smell that some people are sensitive too. To overcome this smell, we suggest that the mat be wiped down with a solution of equal parts lukewarm water and white vinegar, then let it set for five minutes. Afterwards, rinse off the mat and towel dry. Repeat as needed."
I hope it works for you.