Heat behind record number of deaths in Phoenix last year

Extreme heat contributed to more deaths in metropolitan Phoenix last year than initially thought.

The Arizona Republic reported Monday that Maricopa County public health officials recently revised the number of heat-related deaths for 2017 to 172.

The initial tally was 155.

The number marks a record for a second year and an 11 percent increase from the 150 deaths in 2016.

Experts say Arizona’s most populous county has gotten warmer because of an “urban heat island” effect.

Temperatures go up in areas covered in heat-retaining asphalt and concrete, creating health dangers for residents.

Phoenix officials have been tackling the issue by planting trees and promoting lighter-colored asphalt and other reflective construction materials.

Health officials say there have been 18 confirmed heat-related deaths this year. But 128 deaths remain under investigation.