21.   The spill occurred after a tow cable broke.

22.   The spill occurred at Lester B. Pearson International Airport in Toronto.

23.   The spill occurred on Monday while Ornapaper Industries workers were filling a skid tank with medium-grade oil for its boilers.

24.   The spill occurred Thursday evening when a pipe carrying fuel oil from the Samuel H. Armacost tanker to a Pemex onshore facility apparently sprung a leak.

25.   The spill occurred as Omai was negotiating another concession and the government was considering other logging and mining contracts in this Amazon Basin country.

26.   The spill occurred in one of the most impoverished areas of this former communist country.

27.   The spill occurred Saturday after an oil tanker crashed into a pillar as it was trying to dock at an offshore terminal.

28.   The spills often occur at night or during heavy fog, when surveillance is less frequent.

29.   The Water Supply Control Office at Aschaffenburg, just north of where the spill occurred, said the chemical was quickly dissolved in the river water.

30.   The flames were quickly put out by fire-fighting tugboats and no spills occurred.