If toe kick is water damaged you will need to replace it.If just no finished edge you could glue laminate on it or use specialty cabinet trim piece to cover.
Particle board has adhesives in it to hold it together and these off gas. Any laminated product will.
It is far from water proof as you can see from the warpage.
- You can place a new piece of plywood on the bottom of the cabinet over the old warped one to smooth the surface.
- You may have to cut into a few pieces to fit around pipes and through the door.