If you're old enough, you remember the litter-prone, pull-off metal tabs on aluminum cans. And you probably recall when they were replaced by the push-down versions that stay attached to the can.
Now, some environmental groups and legislators in California want the same thing for plastic bottles: They're pushing for a law that mandates caps be tethered or attached to bottles.
You might call it a "tether in their cap." The goals are to cut back on cap litter that becomes marine pollution and to capture the caps for recycling.
By some estimates, cap waste is prevalent. Beach cleanup surveys since 2014 from Ocean Conservancy consistently rank plastic caps the third or fourth most common piece of litter.
Of the 6.9 billion plastic bottles opened each day worldwide, fewer than 1 billion of those caps ultimately get recycled, according to a California company in the tethered- closure business.
But the idea of requiring tethers faces resistance, at least as a legislative mandate. The beverage industry argues reliable technology is not available, and some plastics recyclers worry new cap designs could unintentionally harm their business.
Others in the industry dispute that and say the technology is already here.
Bottled-water maker Crystal Geyser has started using tethered caps on mass-market water bottles in the United States, and one new firm claims its cap technology is ready and is being rolled out, mostly in Asia for now.
California lawmaker Mark Stone, a member of the state Assembly and author of the legislation, points to how the aluminum can industry changed in the 1970s and 1980s with environmental benefits.
"Industry changed in a way that brought forward a product that kept that pull tab captured, that really reduced the amount of that litter going out into the environment," Stone said. "We've proven we can ban plastic bags, we've talked about microbeads, we've talked about [any] number of things.
"It's time that we worked with a process to ensure that when bottles come back to the recycler, they come back with the caps on," he said.
Stone's legislation would require that all plastic bottle caps sold in the state be tethered by 2020. It passed an Assembly committee on a 7-3 vote in early January.
But the legislation has since stalled because it was unable to advance further by a Jan. 30 deadline imposed by California's legislative rules.