Are there any composite/plastic lumber brands that can be used indoor?

I need to build a platform/base in a partially finished basement that occasionally floods. The flood isn’t much, about 1/2 inch, but it does stick around for a bit (at least until the dehumidifier takes care of it). Anything made of wood gets soaked enough to weaken the wood, and is probably a good home for mold. My first thought was to use plastic/composite lumber, as it can get wet without any damage, but I can’t find information on what brands are suitable for indoor use. I’ve heard that some brands have gassing issues. Is there a brand suitable for indoor use?