More than 1,700 Illinois workers received notice in May that they could be laid off in the coming weeks, according to filings with the Illinois Department of Commerce and Economic Opportunity.

Caterpillar warned it could add 299 workers to a round of layoffs planned to begin July 3 at its heavy mining equipment plant in Decatur. The company said in April it would lay off more than 460 supplemental employees there because of falling equipment sales. The combined job cuts represent nearly 20 percent of the plant's workers.

Pennsylvania-based TransCore LP gave notice to 196 workers they could lose their jobs as early as June 30. The company operates the Illinois Tollway Authority's customer-service center in Lisle, warning drivers of violations and taking calls from I-PASS customers.

All Tri-R, a commercial and institutional builder in Decatur, warned 173 workers they could lose their jobs because of a lost contract. On its Web site the company said it had about 300 workers.

Other workers reporting possible layoffs of more than 100 workers included book publisher D. B. Hess in Woodstock, Berkeley Contract Packaging private mail center in Edwardsville, paint manufacturer Testor Corp. in Rockford, Illinois Central School bus in South Beloit as well as school district caterer Chartwells Dining Service in Waukegan. G&D; Integrated Distribution in East Peoria said it may add 168 workers to an earlier WARN notice.

Abbott Laboratories spin-off AbbVie Inc. in North Chicago said it may lay off up to 96 workers between June 21 and the end of the year. The Tribune reported last month AbbView it was cutting pharmaceutical sales representatives who sell heart drugs that have lost patent protection.

Sources said the AbbVie cuts would be nationwide and include "several hundred" employees and contracted salespeople, as well as managers.

Employers with more than 100 employees are required to give 60 days notice of possible layoffs under the federal Worker Adjustment and Retraining (WARN) Act when third of the workforce or more than 500 workers could be affected.