Crossword Genius

Chemicals spread on us: dermatitis (6,8)

Ross

I believe the answer is:

sodium nitrates

I'm a little stuck... Click here to teach me more about this clue!

'chemicals' is the definition.
The answer and definition can be both substances as well as being plural nouns.
Perhaps there's an association between them I don't understand?

I cannot understand how the remainder of the clue works.

Can you help me to learn more?

I've seen this clue in The Independent.
Want a hint initially instead of a full solution? Install my app