Phoenix reached 119 degrees Tuesday, making it one of the hottest days in the city's recorded history.

Such extreme heat can pose health risks, and judging by last year's numbers, heat-related deaths may be on the rise in the Valley.

There were 51 heat-related deaths in the county in 2007. Last year, we saw 130, which Maricopa County Medical Director Rebecca Sunenshine said was the highest the county has ever seen since they started tracking the data.

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Sunenshine said the county does not know the exact cause for the uptick.

"It's probably a combination of factors -- increasing temperatures, possibly the increasing urban heat island," she said.

Eric Katz, the director of Maricopa Medical Center's emergency room, said the most serious cases hurry past the ER.

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"Someone with severe heat reactions will be brought straight in and you may never see them come through the emergency department," he said.

Many people killed by extreme heat end up dying alone.

"Unfortunately, a lot of the people who are in hot indoor spaces without air conditioning are not found till they're already dead," Sunenshine said.