It left damage in extremely treacherous hot coastal wetland (9)

I haven't cracked this one yet — but the brilliant team at Fifteensquared have:

It left damage in extremely treacherous hot coastal wetland SA (=it, i.e. sex appeal) + L (=left) + {MAR (=damage) in [ T <reacherou> S (“extremely” means first and last letters only)]} + H (=hot, as on tap)