Cite as: 524 U. S. 624 (1998)
Opinion of the Court
issue of material fact. Evidence which was merely colorable or not significantly probative would not have been sufficient. Anderson v. Liberty Lobby, Inc., 477 U. S. 242, 249-250 (1986).
We acknowledge the presence of other evidence in the record before the Court of Appeals which, subject to further arguments and examination, might support affirmance of the trial court's ruling. For instance, the record contains substantial testimony from numerous health experts indicating that it is safe to treat patients infected with HIV in dental offices. App. 66-68, 88-90, 264-266, 268. We are unable to determine the import of this evidence, however. The record does not disclose whether the expert testimony submitted by respondent turned on evidence available in September 1994. See id., at 69-70 (expert testimony relied in part on materials published after September 1994).
There are reasons to doubt whether petitioner advanced evidence sufficient to raise a triable issue of fact on the significance of the risk. Petitioner relied on two principal points: First, he asserted that the use of high-speed drills and surface cooling with water created a risk of airborne HIV transmission. The study on which petitioner relied was inconclusive, however, determining only that "[f]urther work is required to determine whether such a risk exists." Johnson & Robinson, Human Immunodeficiency Virus-1 (HIV-1) in the Vapors of Surgical Power Instruments, 33 J. of Medical Virology 47 (1991). Petitioner's expert witness conceded, moreover, that no evidence suggested the spray could transmit HIV. His opinion on airborne risk was based on the absence of contrary evidence, not on positive data. App. 166. Scientific evidence and expert testimony must have a traceable, analytical basis in objective fact before it may be considered on summary judgment. See General Electric Co. v. Joiner, 522 U. S. 136, 144-145, 146 (1997).
Second, petitioner argues that, as of September 1994, CDC had identified seven dental workers with possible occupa-
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