Heat Wave Leaves Midwesterners Reeling : Weather: At least 30 people have died from record temperatures. Warm front moves to East.

A people toughened against the icy reign of winter, Midwesterners found themselves staggered from the other extreme Friday, reeling under a heat wave that has sparked a round of record 100-degree temperatures.

The heat began spreading to the East, where temperatures Friday were already into the mid-90s in many cities. In the nation’s capital, the Washington Monument was closed for a second day after the air conditioning system inside the landmark failed, allowing the internal heat to rise above 100 degrees.

The monument’s air-handling system, which cools the observation level, failed Thursday--prompting officials to shut it due to excessive heat for what was believed to be the first time. Fans were installed as a temporary measure and the monument reopened at 8 a.m. Friday but it had to be closed 6 1/2 hours later.

At least 30 people have died from heat complications since a stagnant weather pattern clamped over the Plains earlier this week, authorities said. The National Weather Service said the high temperatures were expected to last through the weekend.

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The simmering weather claimed a seventh life Friday in Missouri, where four others died earlier in the week. Four of the 11 deaths occurred in Kansas City in homes or apartments without air conditioning, authorities said.

Heat was suspected as the cause of six deaths in Milwaukee and six others in Chicago. Two people each in Kentucky and Iowa died, including a 95-year-old Des Moines woman found dead Friday at home where she had a fan running but just one window open. Texas, Nebraska and Indiana reported one death each related to the heat.

The blasting heat led thousands of Chicagoans to cool down illegally under water hydrants, killed off 200,000 chickens on a northwest Iowa farm and almost caused a trapeze artist to lose his grip during an outdoor performance in Milwaukee. At New York’s Central Park Zoo, the penguins were the big attraction. Their frigid house was so crowded with adults and children seeking refuge from the heat that, for a while, there was a line to get inside.

The Tennessee Valley Authority churned out electricity at a record pace for a third consecutive day as people kept their air conditioners revving.

Sixteen of 53 train cars derailed in Athens, Ohio, about 70 miles southeast of Columbus, because temperatures in the 90s caused the track to shift 14 inches.

Several hundred residents were evacuated because one of the cars leaked dimethylformamide, a combustible solvent.

But they were allowed to return to their homes early Friday, since “what spilled was minuscule,” according to Conrail spokeswoman Christine Wagner. Earlier this week, a freight train derailed near Nebraska City, Neb., because the rail buckled in the heat.

A day after Chicago recorded its hottest day on record--106 degrees--forecasters on Friday expected weather stations throughout the area to climax at between 102 and 105 before nightfall. Sections of Nebraska, Kansas, Missouri, Iowa and Illinois also neared 100 degrees and La Crosse, Wis., tied the all-time high of 108, last reached in 1936.

“It’s particularly rough for Chicago, northern Illinois and southern Wisconsin right now because they’re right in the heart of the front,” said Ken Kunkel, a weather expect at the Midwestern Climate Center on the University of Illinois Champaign-Urbana campus. “That’s why we’re seeing temperatures we haven’t seen in years.”

Firefighters in Chicago doused several large electrical transformers to cool them. On Thursday fireboats were called out to hose down a busy bridge over the Chicago River when the pavement threatened to buckle from the heat.

At midday, those crazy enough to be out on Chicago’s streets seemed to be walking in a daze.

“I should be home now. I should be home now,” was bicycle messenger Joe Staller’s gasping mantra as he took a breather by walking right into a waft of baking air on a downtown street. Clad in a yellow Lycra biker’s outfit that seemed to be sweating on its own, Staller, 40, forgot for the moment that he had parked his bike somewhere else.

The heat was punishing for the normally fleet messengers. Usually able to complete between 30 and 40 trips a day, Staller said he would be lucky to finish 25. “A day like this slows everything down,” he gasped. “Too much traffic. It doesn’t go anywhere. And we don’t have any energy.”

On the city’s South Side, where air conditioners are luxuries for many, teen-agers kept cool by wallowing in streams of water gushing from fire hydrants. More than 3,000 hydrants were illegally opened Thursday and Friday throughout the city--causing the water pressure to drop to precariously low levels, city officials said.

After cavorting in hydrants on Thursday, 6-year-old neighbors Precious Gaston and Keenan Altman joined a wilted column of children bound for a midafternoon boat ride on Lake Michigan on Friday afternoon. Enduring a saunalike ride in a bus from the LeClaire-Hearst Community Center, they clambered aboard the tour boat, hoping for even the briefest flicker of a waterfront breeze.

“I hope they have sodas,” Keenan said. “I’m thirsty again.”

At Kentucky’s Louisville Zoo, keepers turned on sprinklers to water down zebras, antelopes and lions. In Milwaukee, a case of sweaty hands imperiled acrobat George Marinof, who slipped but then caught himself on a trapeze Thursday during a circus performance.

The heat was no less oppressive in the countryside.

By the tens of thousands, animal carcasses lay rotting in the sun across the region, in danger of spoiling before trucks are able to haul them off to rendering plants. Farmers in some areas called for fire trucks to hose down cattle in crowded feedlots.

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More than 200,000 chickens have died since midweek at the Farmegg plant near Humboldt, Iowa, said layer-site manager Russ Dugan. At Storm Lake, Iowa, 120,000 turkeys died in the heat. The Iowa governor’s office reported 2,600 cattle had died, a loss of $1.7 million, along with 337 hogs.

The heavy losses of cattle, fowl and hogs have been concentrated in the northern regions of the Plains. There, “livestock just isn’t as acclimated to these hot summer temperatures as the animals raised further south,” Kunkel said.

Despite the blazing weather and tropical humidity, the warm front appeared to be moving, meteorologists said, showing signs of cooling as it headed toward the East. “The only good thing you can say it will be gone from here by next week,” Kunkel said, adding: “We hope.”

Researcher John Beckham and Times wire services contributed to this story.