Happiness locally about chemical engineer, green inventor (7)

I believe the answer is:

scheele

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This might be a double definition.

'happiness locally about chemical engineer' is the first definition.
I can't judge whether this defines the answer.

'green inventor' is the second definition.
The definition suggests a singular noun which matches the answer.

Can you help me to learn more?

(Another definition for scheele that I've seen is " Swed. chemist, discovered oxygen; leeches (anag.)".)

I've seen this clue in The Times and The Sunday Times.

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