Add a "Hazardous" filter to the Manage Products page
There's currently no way to work on hazardous products without exporting them, but that doesn't let you work on the listings for those products
Do you currently use the product special attribute? If not, you could export all products, filter the hazardous ones out and import “hazardous” in the product special attribute. That way you can work on them within SF. Not ideal but a possible work around for you ?