More than 500 people died during the 10-day heat wave in Spain, Prime Minister Pedro Sanchez revealed Wednesday amid calls for labor arrangements to be adapted to climate change.

Sanchez cited figures released Monday from the Carlos III Health Institute which estimates the number of heat-related deaths based on the number of excess deaths when compared to the average in previous years.

The institute has stressed that these figures are a statistical estimate and not a record of official deaths.

"During this heat wave, more than 500 people died because of such high temperatures, according to the statistics," Sanchez said.

"I ask citizens to exercise extreme caution," he said, noting that the "climate emergency is a reality."

The death of street cleaner Jose Antonio Gonzalez, who collapsed with heat stroke during his shift, is driving a debate in Spain about the need to adapt labor arrangements to climate change.

When Gonzalez started his afternoon shift sweeping the streets of Madrid, the temperature was 40 degrees Celsius amid the heat wave gripping parts of Europe.

After a long time without a job, Gonzalez couldn’t afford to pass up a one-month summer contract to sweep the city, where he lived in a working-class neighborhood. Three hours later, the 60-year-old collapsed with heat stroke and was found lying in the street he was cleaning.

An ambulance took the father of two to the hospital, where he died on Saturday.

The poorest in society, often the elderly and the low-paid such as construction workers and delivery riders for whom heat stress is a workplace hazard, have long been identified as being at a disadvantage in attempts to adjust to rising temperatures.

"It’s obvious that social inequalities play a part" in how much people suffer during heat waves, says Julio Diaz of Spain’s Carlos III Health Institute.

"Enduring a heat wave in an air-conditioned house with a swimming pool is not the same as five people in the same room with a window as the only source of fresh air," he told Spanish public broadcaster RTVE.

In Madrid, Gonzalez’s 21-year-old son, Miguel Angel, says his father, days before he died, had searched on the internet for "how to deal with heat stroke." The evening before he died, he had arrived home from his cleaning shift gasping for air.

Three days after Gonzalez's death, Madrid officials agreed with labor groups that street cleaners could postpone their afternoon shift and work instead amid cooler evening temperatures.

Spain was gripped by a heat wave affecting much of Western Europe which pushed temperatures as high as 45 degrees Celsius in some regions last week, sparking dozens of wildfires.

The blazes forced the evacuation of thousands of people and claimed at least two lives – that of a firefighter and a shepherd who got caught up in the flames in northwest Spain.

The July 9-18 heat wave was one of the most intense ever recorded in Spain, meteorological agency AEMET said Wednesday.

"At a minimum, it is the third most intense heatwave in terms of its geographic extension and duration" since modern records began in 1975, AEMET spokesperson Beatriz Hervella said.

Only two other heat waves lasted longer – one in July 2015 that lasted 26 days and another in August 2003 that went on for 16 days, she added.