No further incidents in the Gold Coast area were reported to Dow until a fish kill in
Koorong Street drain at Southport in February 1997. Water upstream of the weir
contained 1.2 μg/L chlorpyrifos. The most likely cause was thought to be an under
slab treatment, where the pouring of the concrete slab was delayed for 6 days by rain.
Dow responded by communicating the sequence of events to all under slab applicators
in the Gold Coast and Brisbane areas.