Hastings District Council is investigating how methamphetamine has ended up in effluent at its wastewater treatment plant.
Council officials say other regions have seen the chemical turn up washed through drains from drug labs.
Assets Manager David Fraser says it's too early to say if that's what's happening but it is certainly harmful to the plant.
“If you come along and kill a good number of them through having some chemical attack them they’ve just got to come back and restore and you know the shock impact doesn’t help.”
Mr Fraser says the council is trying to work out how to stop it happening again.
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