The prolonged heat wave in the US has led to an increase in severely burned patients who were injured after touching hot surfaces or objects.

According to medics in Arizona, some patients were injured after falling onto asphalt which had been heated by the scorching sun, the BBC reported on Tuesday.

The inside of a car or the dark asphalt surface of a road can be far hotter than the air temperature, research has shown.

Touching metal or asphalt for only a few seconds can be enough to cause severe burns.

Arizona’s capital city of Phoenix has now witnessed a record-breaking 24 consecutive days of temperatures above 43 degrees Celsius, well past the previous record of 18 days set in 1974.

Kevin Foster of the Arizona Burn Centre told the BBC that all of the facility’s 45 hospital beds are currently occupied, and around one-third of those patients have suffered severe contact burns from scorching concrete and asphalt surfaces.

“Summertime is the busy time, so that’s not surprising, but the numbers are a little bit higher than anticipated,” he says, adding that the rate of new patients has outpaced 2022 so far this summer.

Many of the patients are elderly people, who may have fallen after becoming unsteady in the heat, or children who do not get off the ground quickly after falling.

However, he says the “biggest problem” is drug users who are often dehydrated and can faint on sidewalks.

“When people go down to a hot surface and stay there, it only takes 10 to 15 minutes to suffer heat exhaustion, burns and other problems,” Foster told the BBC, adding that some of the burns are deep, third-degree injuries that will require skin grafts.

The centre is also treating over 150 patients who have not been admitted to hospital, but need to be treated for burns sustained touching hot surfaces, such as metal car seat belts.

At least 18 heat-related deaths have occurred in Arizona’s Maricopa County since April, with 69 more fatalities under investigation.

Meanwhile, the ongoing heatwave, caused by a “heat dome” or a large area of high pressure, baking the US Southwest for weeks is set to expand into central and eastern regions, reports the BBC.

According to meteorologists, beginning in the Midwest, the hot weather will extend east as far as the southern tip of Florida by Wednesday.

Temperature records were surpassed in several major cities over the weekend, and some 59 million Americans began on Monday under extreme heat advisories.

In the border town of El Paso, Texas, residents experienced a 38th consecutive day at temperatures above 38 degrees Celsius.

The National Park Service has also reported at least four deaths among visitors.

Two female hikers were found dead in the Valley of Fire State Park in Nevada on Sunday, amid temperatures as high as 45 degrees, the BBC reported.

Ocean temperatures in South Florida and the Keys could reach unprecedented highs.

July is now expected to be the Earth’s hottest month since records began.

Data from the National Oceanic and Atmospheric Administration shows the US has this year set or tied more than 13,000 high temperature records, as well as 16,000 low temperature records.