Many types of masks, including the most common surgical variety, contain plastics that taint ocean ecosystems and disrupt marine food chains. The bottom line is that, in the era of covid-19, another form of mass-produced human stuff is making its way into places where humans do not live.

“Whatever the product may be this is a new, additional plastic threat,” said Adam Ratner, associate director of the conservation education program at the Marine Mammal Center based in the Marin headlands, which rescues and heals seals, sea lions, otters and other animals along a 600-mile stretch of California coast.

So far, Ratner said, no animals have needed to be rescued after being entangled in personal protective items. It is the extent of the pollution that is the primary concern, he said, given that 25 percent of the animals they treat already suffer from the harmful effects of ocean trash.

“We want to see people use masks, we want to see people use all of the protective equipment and stay healthy,” Ratner said. “But now is the time to stop this, and ocean trash knows no international borders.”