Exhibit 23.1 CONSENT OF INDEPENDENT PUBLIC ACCOUNTANTS As independent public accountants, we hereby consent to the incorporation of our report dated February 11, 2002 included in this Form 10-K, into the Company's previously filed Registration Statements on Forms S-3 and S-8 (File nos. 333-73026, 333-09165, 333-49231, 333-90845, 333-51684, and 333-67982). /s/ Arthur Andersen LLP Arthur Andersen LLP Chicago, Illinois March 29, 2002