Why Oysters are Shacking up in Old Subway Cars

States scrap over metal in a race to boast the greenest reef.

In 2001, New York City had over 1,000 outdated subway cars on its hands. When they were first introduced in 1959, the old Redbird trains were gorgeous machines, but after four decades of service, it was time for the battered cars to be permanently retired. But rather than take them to a slag heap to be salvaged for scrap or crushed into little metal cubes, the city took 619 of the cars, stripped them of their windows and oily undercarriages, steam cleaned them, and then hauled the 20,000 pound metal boxes down to Delaware on a freighter ship. Then they dumped them all into the sea.

This wasn’t some fit of insanity or outburst of ecocidal rage. Quite the opposite, actually—dumping the city’s old subway cars into the water was just the first step in an effort to create new, artificial reefs off the eastern seaboard. By the dawn of the 21st century, most of the coastline of the mid-Atlantic states was a lifeless underwater desert. It lacked the nooks, crannies , and flat, porous surfaces in which oysters, blue mussels, and local fish, like the black sea bass, make their homes. Subway cars formed the groundwork to restore that habitat and revitalize local shoreline ecosystems. By 2003, New York had dumped over 1,250 cars off the coasts of Delaware, Georgia, New Jersey, South Carolina, and Virginia. They were mutually beneficial arrangements; by offering to haul and dump the trains to the recipient states for free, New York was able to avoid the high cost of dumping the mass of scrap metal. In 2007 , the incredible successes of the first reef project led to a national scramble, as states vied for the next 1,000 or so retiring cars to be sent their way.

New York’s subway cars aren’t the world’s first artificial reefs: As early as the 1600s , Japanese seaside communities used rubble and construction materials to create little kelp sanctuaries, and by the 1830s, South Carolinians were using reefs made of old logs to bolster fishing yields. Nowadays, you’ll find artificial reefs playing a big role in the shore ecosystems of cities like Aqaba, Jordan, Cancun, Mexico, and Wellington, New Zealand. Florida is especially fond of sinking decommissioned ships to form new reefs. (They once tried to use two million loose tires instead, but paid the price when many drifted away in the currents, thus becoming pollutants).

Illustration by Tyler Hoehne

Since 1995, Delaware has been leading the charge to build artificial reefs in America. A year before the Redbird cars arrived, Delaware had already dropped tons of concrete, thousands of weighted tires, 86 military vehicles, and two sunken ships off their coast at 14 artificial reef sites. Other states, initially fearing that subway cars and similar human detritus could prove toxic to the environment in some unexpected way, stood watching the experiment cautiously— but Delaware’s gung-ho enthusiasm paid off, and by 2003 their once barren waters had developed a fish overcrowding problem .

For many in New York, the highlight of the subway reefs are their potential to revive oyster populations—a goal many environmental and civic groups in the area share. Until the dawn of the 20th century, New York was a hotbed of quality oyster fishing, but as oyster populations declined, so did their bacteria-and-toxin-eating benefits, and pollution slowly ravaged the city’s coastlines.

Over the past few years, groups like the New York Harbor Foundation’s Billion Oyster Project have sprung up all over New York, creating mini-habitats for oysters as a means to clean up the waterways and restore them to habitable, usable environments. As of 2013, one organization alone, NY/NJ Baykeeper , boasted about 45 operational oyster bed sites. Landscape architect Kate Orff has begun designing visions of a revived waterfront, integrated into modern city life. The idea of harmonious integration, which might’ve seemed hopeless at one point—cities are often painted as direct adversaries of nature—now suddenly doesn’t seem so farfetched. As oyster revivals kick off over hundreds of miles of coastline, there’s growing promise in the belief that cities can indeed play positive roles in repairing the environment.