ST. LOUIS – The St. Louis heat wave which may last the rest of the week is raising health concerns.

Construction workers have to be outside in the heat but some workers start their jobs early in the morning when it’s a bit cooler.

“I mean you still got a job to do no matter how it is like I said drink plenty of fluids try to stay as cool as possible,” said Jeff Thomas, who is a concrete finisher.

“Sometime in the mornings, it’s still in the 80s for the early morning walkers. We do see an increase with the walkers in the morning as well,” said Sean Phillips, Senior Marketing Director at the West County Center.

If you’re trying to find a cool place to escape the heat, St. Louis city is utilizing all 16 of its library branches as cooling centers. Anyone can go into the centers when they are open.

“There are always options at the library, there’s the computers they can access, there’s obviously all the great materials for them to check out,” said Maryann Brickey, St. Louis library Director of Central Services. “For children under the age of 18, we also have a partnership with operation food search where they’re serving meals this summer at five of our locations.”

Medical experts said all of these efforts to beat the heat are critical because the temperatures and humidity moving in the St. Louis area are dangerous.

“If you must be outside know that you can’t be out there very long,” said Dr. Robert Poirer, Emergency Medicine at Barnes-Jewish Hospital. “As soon as you start having any symptoms, you should immediately move indoors and start cooling yourself down. Heat exhaustion can quickly move into heat stroke if you don’t take the necessary steps to start treating it and heat stroke is deadly.”

Doctors said a person who has to be outside can become overheated within 30 minutes.