 Trafigura claims that this was done under agreement that the waste would be treated and disposed of legally, and that the substance was waste ("slops") from the routine washing of "Probo Koala"'s tanks.Again according to Trafigura, it became apparent that the untreated slops had been dumped illegally at municipal refuse dumps.They contend that the slops were an alkaline mix of water, gasoline, and caustic soda, along with a very small amount of foul-smelling and toxic hydrogen sulfide.