In several countries around the world, authorities have found what they thought was a great solution to getting rid of old tyres, sink them in the ocean and create an artificial reef for new ecosystems to develop. This was started in the 1980's and not only did very few marine species take to growing on them, very little thought was given to how the tyres would fair with the ocean currents. Sure enough, fish opted for natural reefs or even artificial ones made of concrete and with many tyres drifting far and wide under the water it could be seen as environmental disaster! To add insult to injury, not only were they not being inhabited and drifting all over the sea bed, they were also found leaking chemicals including heavy metals into the surrounding water. At one such reef in 2015 (just 500m of the shore in Cannes France) 25,000 tyres were removed in a single year with a further 10,000 expected to be removed before 2019. The French government are paying for the majority of the clean up but tyre manufacturer Michelin are also contributing. Other disastrous tyre reefs have been created in Gibraltar and Florida
https://www.thelocal.fr/20180923/france-reverses-car-tyre-sea-sanctuary-an-environmental-flop