Approximately two million old car tire's are on the ocean floor off Fort Lauderdale in the US, dumped in the 1970s with the intent of creating an artificial reef.
The tires are now scouring the ocean floor and wedging against the natural reef, killing coral.
"There are no really historical records of the volume and type of material that was spilled in the oceans before the establishment of an anti-dumping law. However, it is estimated that in 1968, 38 million tons of excavated material, 4.5 million tons of industrial waste, 4.5 million sewage sludge, 100 million tons of petroleum-based product (plastic), 2 to 4 tonnes of chemical waste, more than 1 million tons of heavy metals were released into the ocean. The U.S. archive shows that between 1946 and 1970 over 55,000 containers of radioactive waste were disposed in 3 sites of dumping of the Pacific Ocean. In addition, 34,000 tons of radioactive wastes were disposed in 3 sites of dumping of the U.S. east coast between 1951 and 1962. No law on dumping radioactive waste has been put into force before 1972."