DENVER (KDVR) — Colorado’s high cost of living is indeed a struggle for low-wage workers.

The union representing King Soopers employees in and around Denver and Colorado Springs voted to strike beginning Jan. 12. The union claims unfair labor practices and lower wages than what’s needed to live in Colorado.

By one metric, low-wage workers are earning less than the minimum to survive in one of the nation’s most expensive locations.

The “living standard” is a tool used to calculate how much a worker needs to earn in order to afford the basic necessities without slipping into debt. It is far below a comfortable middle-class existence, but it is higher than the federal poverty threshold, which only accounts for basic materials like food and shelter but not broadband, child care or civic engagement costs.

A living wage is the minimum income necessary for someone to be able to meet their basic needs.

Colorado’s statewide minimum wage pays about $10,000 less per year than the living wage needed for a single adult with no children to meet basic needs, according to a database of current living wages published by the Massachusetts Institute of Technology.

UFCW Local 7 union president Kim Cordova wrote in a letter last October that she wanted King Soopers to pay all Colorado employees the Denver minimum wage of $15.87 rather than the state’s $12.56 minimum wage rate. In response, King Soopers management said the average associated wage is $18.29, which would cover the living wage for a childless adult.

Union negotiations are inflamed by Colorado’s and Denver’s stratospheric leaps in living costs over the past decade.

According to MIT, Colorado has the nation’s eighth-highest living wage. This makes it the most expensive state in the interior United States, and even more expensive than several coastal states, including Washington.

The Denver-Lakewood-Aurora metro statistical area tops the chart of the country’s most expensive cities.

Among the 100 largest U.S. metro areas, it ranks 13th-highest for a living wage.