Workers throughout Chicago were numbed and saddened by the horrors they watched unfold in Manhattan and Washington on Tuesday morning.

But perhaps the most intense emotions came from the floors of Chicago's derivatives exchanges, where employees talk daily with friends and colleagues at the World Trade Center.

Most exchange workers assumed the first airplane's collision with the building was an accident. But when the second plane struck, the atmosphere changed.

"People were yelling that they should close the exchange," said Fred Schick, a clerk at the Chicago Board of Trade.

But trading continued until 9:15 a.m., and despite active trading, the noise died down as the horror of the situation set in.

"It wasn't as loud as a good market panic," Schick said. "You could tell it wasn't just the market. It's one thing when money is dissolving; it's another thing when life is dissolving."

Many Chicago exchange employees tried to reach colleagues at the World Trade Center.

At the Chicago Mercantile Exchange, word spread that a trader in the Eurodollar pit had been on the phone with a customer in New York who suddenly started yelling, "I'm dying, I'm dying."

Mike Komaransky, a runner in the pit who heard about that chilling episode, said that finally "most people stopped trading and just crowded around TVs. It was too hard to concentrate and trade at that point."

Exchange workers feared for their own lives as well.

"People wanted out of the building, because it's a financial institution that's very important to the country," said James Quain, an independent trader at the Board of Trade.

Pat Murphy began looking for airplanes out the 18th-floor window of his Merc office, and he called his 3-year-old daughter, Nellie, and 1-year-old son, Jake.

"I said, `I love you guys, and I hope I see you later,'" Murphy recalled.

Then he tried to call Denise Mangin, a colleague at the World Trade Center to whom he speaks seven or eight times a day. He couldn't get through.

Finally, Murphy sent an e-mail: "I hope God's watching over you. I hope you're alive. Pat."

At 10:20 a.m., Merc trader Mick Hyland still had not reached his son in Staten Island or his friend Bill White, a Chicago Board Options Exchange representative who works at the World Trade Center. "I have no thoughts until I hear from them," he said.

Leonard Schwalbach, a trade checker at the Merc, still watched the Chicago sky for airplanes while he waited for a ride home after 10 a.m. Tuesday.

"I'm still trying to figure it out," he said. "I hate to be dramatic, but I think what we saw this morning is going to change all our lives."