Damage in shallow waters is most often caused by oil becoming mixed into the water column by strong wave action or by the inappropriate use of dispersants too close to the shore. In many circumstances the dilution capacity, for example due to tidal flushing, is sufficient to keep concentrations of oil in the water below harmful levels. On the other hand, where light refined products or light crude oils have become dispersed into shallow water leading to high concentrations of the toxic components of oil, mortality of bottom-dwelling (benthic) animals and those living in the sediment has occurred.