Nervous traffic managers began leafing through their files for contingency

plans Thursday as they learned that the Teamsters union has given United Parcel Service five-days' notice that it may strike the giant package carrier by Sept. 30.

"We'll start looking at our alter- natives and we'll warn sales that anything critical beyond Zone 5 (1,500 to 2,000 miles), has to move motor carrier minimum charge," said Thomas L. Harshman, manager of transportation operations for Baxter Healthcare Corp. of Deerfield, Ill. "With the weekend, we'll be coming close to the end of the five-day period and we don't anything to get caught."Shipping motor carrier minimum charge is costly because many companies will end up paying for a lot of empty space, Mr. Harshman said. However, in some cases, air freight may be cheaper than the minimum trucking charge.

John Quinn, transportation coordinator for Johnson & Johnson Hospital Services Inc. of New Brunswick, N.J., said the union's move is a big surprise.

But even though his company set up a contingency plan months ago that adopts a phased-in alternative shipping approach, J&J will have to examine events over the weekend before implementing it, he said.

The Teamsters union, fighting to win a new pact for 165,000 members, told UPS late Wednesday that by midnight Sept. 29 it "will take such action as it deems necessary to win a fair contract for its members, up to and including a strike."

"A UPS guy called this morning and said he had some contract information and he sounded glum," said a traffic official Thursday for Nike Inc. of Wilsonville, Ore.

Most shippers said they were surprised that the Teamsters are playing such hardball with the world's largest transportation company.

Like many traffic managers, Bill Johnson, director of distribution for Lands' End Inc. of Dodgeville, Wis., said he felt all along that the Teamsters' moves were mostly negotiating ploys. But this latest action, he said, signifies that it's time for Lands' End to determine what alternatives it may have in the event of a strike against UPS.

Some traffic managers still doubt that the Teamsters will walk.

"I still can't believe they'd do it. They would lose millions of

dollars," said Vicki Hamel, mail-room supervisor for the Home Shopping Network of Clearwater, Fla.

"What UPS offered them doesn't sound too bad. But the new three-day service using non-union workers is a sticky point," Ms. Hamel said.