Hank, a Spokane man's dog, was killed while walking down the street in February. 

Later, an engineer's analysis determined he was killed by stray voltage from the deicing system beneath the sidewalk outside Washington Trust Bank.

In response, the dog's owner began working with the Spokane City Council to draft measures that could prevent similar tragedies from occurring again.

The result: "Hank's Law," an ordinance passed unanimously on Monday.

Here's a breakdown of exactly how it aims to stop future electrocutions.

To understand the problem, you first must understand why the sidewalk heater was fatal to begin with.

There were a few factors. One: A break in the wiring's insulation. Two: A wet sidewalk. Three: A highly conductive deicing salt placed on the walk.

The current also affected Hank more severely than it did his owner because the current goes right past an animal's heart. 

The engineer who analyzed the incident said it could've been prevented with a simple device: A ground fault circuit interrupter.

That device basically detects if the proper current is broken and then instantly shuts off the power. Similar devices are found on many power outlets, especially in bathrooms.

These devices have been required in all sidewalk heating systems since 1993. But the device that killed Hank was installed in 1973.

Until now, businesses were not required to retroactively install the circuit breakers.

That brings us to the first thing that Hank's Law does: It requires every sidewalk heater in the city to have the circuit breaker. That means some businesses might have to upgrade.

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Councilman Breean Beggs says he does not expect the cost of those upgrades to be significant.

The law also addressed a second concern that arose after Hank's death: We don't really know where these systems are located. 

There's no database of sidewalk heaters and whether or not they have circuit breakers. This law will create such a registry.

Property owners will be required to fill out a form notifying the city that they have a sidewalk heater. They'll also be required to test the system once a year.

Assuming the mayor doesn't veto the ordinance, it will go into effect in August. But property owners will get a year to upgrade their systems and to join the registry.

After that year has passed, violators can be fined.

Beggs said permanently shutting down outdated sidewalk heating systems and not upgrading will remain an option but it has to be permanently disabled, meaning no other future property owner could simply flip it back on.

Washington Trust Bank has permanently disabled their system.

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