Evidence Code section 646, subdivision (b) defines res ipsa loquitur as "a presumption affecting the burden of producing evidence." the presumption arises when the evidence establishes: (1) the accident was of a kind which ordinarily does not occur in the absence of someone's negligence; (2) the accident was caused by an agency or instrumentality within the exclusive control of the defendant; (3) the accident was not due to any voluntary action or contribution on the part of the plaintiff. (Brown v. Poway Unified School Dist., supra, 4 Cal.4th at pp. 825-826.) In Brown v. Poway Unified School Dist. (1993) 4 Cal.4th 820, 825, the Supreme Court explained that "certain kinds of accidents are so likely to have been caused by the defendant's negligence that one may fairly say 'the thing speaks for itself.' The Latin equivalent of this phrase, 'res ipsa loquitur,' was first applied to a barrel of flour that rolled out of the window of the defendant's warehouse onto the plaintiff. (Byrne v. Boadle (1863) 159 Eng.Rep. 299, 300.) As later courts repeated the phrase, it evolved into the name of a rule for determining whether circumstantial evidence of negligence is sufficient." The doctrine "is applied in a wide variety of situations, including cases of medical or dental treatment and hospital care." (Ybarra v. Spangard (1944) 25 Cal.2d 486, 489.)