There have been a number of stories in the news regarding whales found dead with many pounds of plastic in their bodies. The amount of plastic found inside of large marine mammals has been as high as 88 pounds. The New York Times’ latest article from April 2nd, reports 48 pounds of plastic inside the whale’s body. https://www.nytimes.com/2019/04/02/world/europe/plastic-whale-dead-italy.html.
Since steel is an alloy made primarily from iron, a mineral, combined with carbon, it will biodegrade over time. Cans made from steel do not float in the ocean or break into particles that end up in marine life.
In addition, closed loop, curbside recycling is an incentive to use and recycle steel cans. They have been around for decades and have never had to change their earth-friendly claim.