In 2015, 4,700 people in the US lost a finger or other body part to table-saw incidents. Most of those injuries didn't have to happen, thanks to technology invented in 1999 by entrepreneur Stephen Gass. By giving his blade a slight electric charge, his saw is able to detect contact with a human hand and stop spinning in a few milliseconds. A widely circulated video shows a test on a hot dog that leaves the wiener unscathed.

Now federal regulators are considering whether to make Gass' technology mandatory in the table-saw industry. The Consumer Product Safety Commission announced plans for a new rule in May, and the rules could take effect in the coming months.

But established makers of power tools vehemently object. They say the mandate could double the cost of entry-level table saws and destroy jobs in the power-tool industry. They also point out that Gass holds dozens of patents on the technology. If the CPSC makes the technology mandatory for table saws, that could give Gass a legal monopoly over the table-saw industry until at least 2021, when his oldest patents expire.

At the same time, table-saw related injuries cost society billions every year. The CPSC predicts switching to the safer saw design will save society $1,500 to $4,000 per saw sold by reducing medical bills and lost work.

"You commissioners have the power to take one of the most dangerous products ever available to consumers and make it vastly safer," Gass said at a CPSC public hearing on Wednesday.

Gass has quarreled with power tool makers for years

Gass didn't just invent a safer table saw; he has also been a driving force behind its adoption over the last two decades. In the early 2000s, he tried to get established table-saw makers interested in licensing the technology, asking for an eight-percent cut of table-saw revenue. But none of the companies accepted the deal.

So Gass' company, SawStop, began manufacturing its own table saws with the technology. He also petitioned federal regulators to make active safety technology, like the one he invented, mandatory across the industry.

Meanwhile, established toolmakers started working on safety technology of their own. Finally in 2015, Bosch introduced the first SawStop competitor, a table saw called the Reaxx.

Like the SawStop, the Reaxx uses a small electric charge to sense contact with human flesh. But the two designs use different mechanisms to pull the blade away from the user before he or she gets injured.

The SawStop jams a brake directly into the teeth of the sawblade, stopping it instantly. As the blade stops, its angular momentum forces the blade downward and causes it to retract rapidly into the table. A shortcoming of this approach is that the blade is damaged in the process, requiring a replacement.

By contrast, the Bosch saw uses an airbag-style cartridge to push the blade downward at high speed, allowing it to continue spinning as it drops. As a result, the blade isn't damaged, and the saw can be up and running more quickly.

Despite these differences, SawStop accused Bosch of infringing its patents. In January, the International Trade Commission sided with SawStop and blocked sale of the Bosch table saw.

And that creates an obvious concern for the CPSC: if SawStop's patents are broad enough to cover even competing safety technologies like the one Bosch developed, it might be impossible to invent around the patents. This creates a risk that mandating the use of the technology could give SawStop a de facto legal monopoly over the entire table saw market.

On the other hand, Gass has told the CPSC that his company would license its patents to competitors for an eight-percent cut of their table-saw revenue—though that promise might not be legally binding. And Gass' patents won't be in effect forever. The most important patents were filed in 2001, which means they'll expire by 2021.

Table-saw makers face a wave of lawsuits

Beyond a possible CPSC mandate, the other big danger facing table-saw manufacturers who don't adopt the new technology is product-liability lawsuits.

Before the invention of the SawStop technology, power-tool makers could argue that table saws were just an inherently dangerous product, and customers accepted the risk when they chose to buy and operate them. But now that technology like SawStop exists, plaintiffs have begun to argue that the absence of the technology constitutes a dangerous design defect.

A Massachusetts plaintiff won a lawsuit with this argument in 2010. There have been others since then, including one in Illinois in 2014 and another in Pennsylvania in 2017.