Question

How is naphthalene used in the household? Does it constitute a health hazard?

Answer 1

You mean the naphthalene cakes that you see on the bottom of urinals?

Explanation:

The answer to your question is `"not much"`. Of course the people who supply `"moth balls"` will machine the napthelene so that it conveniently fits in a pocket. The naphthalene cakes used in toilets (which we used to call `"trough lollies"`) are machined so that they are physically large, and (maybe) brightly coloured, and maybe with some perfume. So the difference is basically just the appearance.