1 EXHIBIT 99.1 CONSENT OF SOLOMON ASSOCIATES We hereby consent to the use in the 2000 Form 10-K of Conoco Inc., of our name in reference to ranking of the performance of Conoco's European refineries which appear in such 2000 Form 10-K, to be filed on or about March 15, 2001. We also consent to the reference to us as "an independent benchmarking company." /s/ D. B. Bossung Executive Vice President Solomon Associates, Inc. February 20, 2001