Widespread Heat Warnings Issued

Hundreds of people were treated for heat-related health problems as the Midwest sizzled under oppressively hot weather. Weather Services Corp. said much of the Midwest and the Mississippi Valley were under the threat of dangerously hot conditions. A break in the heat and humidity was not expected until Monday. The National Weather Service placed Chicago and St. Louis, where temperatures climbed into the mid- to upper-90s and the heat index neared 115 degrees, under an extreme heat warning, meaning that the heat will cause health problems.