Re: the manufacture of wood windows. You're correct about softwoods needing more preservative than hardwoods. This also applies to wood doors. Woods such as mahogany, teak, redwood and cedar have natural decay resistant properties so there's no need to add additional chemicals. However, some people may be sensitive to these woods as well. Best bet? Contact the manufacturer and ask specific questions about the chemicals it uses. It will require digging. In other words, you'll have to talk to more than one person. And, of course, request a MSDS sheet. Good luck.
