Plastic is everywhere, an essential component in cars, planes, spaceships — but also in countless mundane products such as deodorant canisters, razors and food packaging. Modern life is inconceivable without it.

But the astonishing amount of plastic humanity uses also has a massive and accelerating environmental impact. Some 8 million tons of plastic flow into the ocean every year. The debris in a vast swath of the North Pacific Ocean known as the Great Pacific Garbage Patch is a huge aggregation of shoes, fishing nets, bags and other trash. Less visible but also plentiful are tiny “microplastics” made of weathered plastic products, which float around the water column in which all sorts of marine animals feed. Weathered plastics also make the water murkier, blocking sunlight from reaching plankton and other keystone species in the food chain. According to one estimate, the tonnage of plastic in the seas could outweigh that of fish by mid-century.

The answer is seemingly obvious: People throw their food containers into the recycling bin instead of the trash can when they are finished with them. But only about 9 percent of plastic waste is recycled in the United States. The rest piles up, makes its way into the ocean or gets burned, which produces greenhouse gas emissions. This is partially because some Americans do not recycle vigilantly. A larger problem is that it is often simply cheaper to buy “virgin” plastics rather than recycled material.

Sen. Sheldon Whitehouse (D-R.I.) has introduced a bill that would help. He would place a 20 cent-per-pound tax on virgin plastics sold to make single-use products. So the levy would not be placed on plastics used to produce seats or solar panels, but it would encourage companies that, say, package meals in single-use containers to seek recycled material.

The plastics industry objects that it is doing enough without the government nudge, investing in advanced recycling technologies because major corporate customers demand more sustainable materials. But if their efforts are as effective as they say, they should have nothing to worry about federal policy that ensures they stay on track. For decades, the industry has been allowed to produce a material that has a substantial environmental impact that is not reflected in its cost. This is an implicit subsidy that is causing increasingly severe ecological problems.

The industry also argues that taxing virgin plastics would encourage companies and consumers to substitute plastic goods with things made of other materials, such as paper and glass. These are heavier and therefore produce more fossil fuels than plastic does to create and transport. But the nation is on its way to decarbonizing the electricity and transportation sectors, promising to lessen any such impacts; plastic-filled oceans are a unique environmental threat for which a specific policy response is still required.

Democrats are considering Mr. Whitehouse’s tax to help pay for their big reconciliation spending bill. Whether it makes its way into that package or comes up on its own, it is worth approving.