hardy plank is a cement-fiber material and is not affected by humidity. James hardy recommends wearing protective mask when cutting-drilling their products. cement dust is at the least an irritante so be safe, wear a good filter mask, not the paper mask that is sold as a “painters mask” that is only good to keep your face clean, not filter dust as they do not fit well enough to do any good. get a good hepa mask such as the 3M that sells for around $20 dollars.