Colossal wastage of coal? (4)

I believe the answer is:

loss

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

'wastage of coal?' is the definition.
'loss' can be an answer for 'wastage' (thesaurus). I'm not sure about the 'of coal?' bit.

'colossal' is the wordplay.
'LOSS' is hidden in amongst the letters.
However, I'm uncertain how this is indicated.

Can you help me to learn more?

(Other definitions for loss that I've seen before include "(Sports) defeat" , "Disadvantage" , "(Sporting) defeat" , "disappearance" , "Failure to profit or succeed" .)

I've seen this clue in the Evening Standard.

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