This study assessed the dermal carcinogenic potential of raw bitumen derived from the Cold Lake Oil Sands deposit (located in Northeast Alberta, Canada) and two liquids which were under evaluation as part of a process tad refine the crude bitumen at the Cold Lake site. The crude bitumen was dermally carcinogenic, inducing tumors in 2606 of the treated animals with a median latency of 106 weeks. This response was significantly greater than the tumor yield previously reported for a raw bitumen derived from Athabasca tar sands by the Syncrude process, but was not substantially different from the carcinogenic potential of two crude petroleum oils. The GO-FINING product, a high boiling (259-5 19"C), catalytically cracked gas oil was a relatively potent dermal carcinogen, inducing tumors in 86% of the treated animals with a median latency of 46 weeks. This result is consistent with the fact that the GO-FINHNG product contained appreciable levels of high boiling aromatic compounds. The HYCRACK- ING product, a high boiling (102-498"C), severely hydroprocessed liquid was noncarcinogenic. This result was also consistent with the compositional data; the high boiling components were predominantly saturated species. Thus the carcinogenic properties of the liquid products prepared by these two processes were as predicted from the compositional information.