Checks for disease when sea is covering coastal state (8)

I believe the answer is:

medicals

'checks for disease' is the definition.
(medical inspections)

'sea is covering coastal state' is the wordplay.
'sea' becomes 'med' (short for Mediterranean).
'covering' is an insertion indicator.
'coastal state' becomes 'Cal' (abbreviation for California).
'is' placed around 'cal' is 'icals'.
'med'+'icals'='MEDICALS'

'when' acts as a link.

(Another definition for medicals that I've seen is " health checks".)

I've seen this clue in The Guardian.

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