If you think subway cars are only useful so long as they are efficiently carrying urban travelers from point A to point B, well, you're wrong! It turns out that hundreds of retired New York City subway cars have been finding a second home--80 feet underwater, and 16 nautical miles off the coast of Delaware. There they are helping to transform "a barren stretch of ocean floor into a bountiful oasis, carpeted in sea grasses, walled thick with blue mussels and sponges, and teeming with black sea bass and tautog." So far, 666 subway cars have already made their way to the ocean floor, and the results have been impressive: "a 400-fold increase in the amount of marine food per square foot in the last seven years," and "In the last several years, the reefs have drawn swift open-ocean fish, like tuna and mackerel, that use the reefs as hunting grounds for smaller prey. Sea bass like to live inside the cars, while large flounder lie in the silt that settles on top of the cars." This is great news, as ocean acidification from climate change and other human disruptions are harming reefs around the world.
So what about the environmental impacts from the subway cars themselves?
Some environmental groups, such as the American Littoral Society, "opposed the use of the Redbird cars because they have small levels of asbestos in the glue used to secure the floor panels and in the insulation material in the walls." However, "State and federal environmental officials approved the use of the Redbirds and other cars for artificial reefs in Delaware and elsewhere because they said the asbestos was not a risk for marine life and has to be airborne to pose a threat to humans."
The only significant problem, it seems, is that other states are catching on to the trend, but unfortunately there is only a limited number of retired subway cars available. As a result, "States have experimented with other types of artificial reef materials, including abandoned automobiles, tanks, refrigerators, shopping carts and washing machines." But none have worked very well; the fish seem to like the roominess of the subway cars, and their weight ensures that the structure stays stably anchored to the sea bed. Besides, while the environmental impacts of dumping subway cars are, at worst, minimal, it doesn't seem like a great idea to begin throwing all our abandoned appliances in the sea in the hopes of restoring aquatic ecosystems...