Darrick Gerano says scuba diving in the Allegheny River ranges from unpleasant to downright harrowing. The water is cold and murky. Vision often is limited to just a few feet.

Tree branches and junk dumped into the river pose a constant threat of entanglement. And then there are the dead bodies. “It’s not a fun job,” said Gerano, director of Murrysville Medic One.

“It’s not like we’re going to the Caribbean and swimming with a bunch of beautiful fish.” There’s no telling how many bodies are in Southwestern Pennsylvania’s rivers, but Gerano has stumbled across human remains eight times in the past five years. Just last month, his team was conducting a training dive in Springdale when they discovered the remains of Bunnie Lee trapped inside his Mazda.

The 78-year-old man from East Liberty, who is believed to have suffered from dementia, had been missing since 2013. A few weeks later, the remains of Janet Walsh, 70, of Shaler were discovered in a submerged vehicle in Oakmont. She had been missing for nearly five years.

Both remains were found by coincidence. Some online and social media commenters have suggested authorities should scan the region’s three rivers for remains in a single, coordinated effort to bring closure to as many families as possible. But that would be nearly impossible, according to expert divers, sonar operators and cold case specialists.

Richard Linn, operations chief for Pittsburgh River Rescue, describes a recovery dive like “trying .