Five years ago, Rich Mason’s friends lamented the numerous frogs and toads that turned up in their backyard swimming pool skimmer baskets, dead or impaired from the chemicals. One particularly warm, rainy night yielded more than 50 amphibian casualties, they reported.

Mason, a wildlife biologist for the U.S. Fish and Wildlife Service, began asking around, and other pool-owning friends also complained of amphibian death tolls. Occasionally, frogs were spotted swimming, or balanced on the floating balls that keep pool vacuum hoses afloat.

“Frogs seek anything to get out of the water,” says Mason, who lives near Annapolis, Md. “It just killed me that these frogs were dying.” These aquatic animals don’t drown in pools; the chlorine seeps into their permeable skin and poisons their bloodstreams. When an amphibian accidentally jumps in, it swims to the pool’s wall and bumps along until it finds something to climb onto. A frog could be dead within hours if it doesn’t find an exit. “Being a wildlife biologist, I thought, this doesn’t seem right,” Mason says.

While pools pose little danger to populations of common frogs and toads, rarer species have more to lose. For some endangered frog species in California and other parts of the country, Mason says, losing a few individuals could threaten populations.

Now, after years of design and testing, Froglog is a patent-pending invention that provides amphibians — as well as small mammals such as chipmunks — an escape route from pools. A thick foam tile with angled edges allows a small creature to crawl up out of the water; then a plastic mesh ramp, stabilized by two thin pieces of plastic (cut from vinyl siding) leads to the pool’s deck, where a beanbag-sized, canvas bag full of sand holds the contraption in place.

Like any good inventor, Mason did his homework first: He searched for research or studies that might have been done on amphibians and pools, but came up empty-handed. He even tapped into a network of herpetologist friends, and though anecdotal stories surfaced, the subject has been untouched by science.

He scouted for other devices on the market that help animals escape swimming pools, and found one designed for larger animals, such as dogs and cats, that had to be drilled into the concrete pool deck. “I thought for most people, that wasn’t the answer,” he says.

So Mason formed the first Froglog from scrap foam and canvas from a local boating shop. A tinkerer at heart, Mason even fashioned a guillotine-like device using a can-crusher to punch a slot for the mesh ramp through the foam, which he shaped with a table saw, band saw and router. He tested and tweaked the design for size, shape and flexibility, allowing for varying water levels in pools, and built a funneled trap at the top of one Froglog to test if his invention was working. It was: In one night he found a handful of frogs waiting safely in the trap.

Mason regularly sells a couple hundred Froglogs each summer. Selling the $21 device is not a moneymaking venture — only now is Mason barely breaking even with his initial $15,000 investment. Instead, Mason sells Froglogs because he believes frogs shouldn’t needlessly perish in swimming pools.

“My main goal is to have it more widely used,” Mason says. “It’s doing some good.”

Customers hail from around the U.S., Canada, Europe and Australia. And though the Froglog works for chipmunks and moles, one European company requested that Mason design a version sturdy enough for hedgehogs.

“We need to get into the tropics, too,” he says, because of the large diversity of amphibians and large number of swimming pools at hotels and resorts. Mason’s next move for his fledgling business may be to link up with a large international swimming pool supply company that would launch Froglogs around the world.