delivered the opinion of the court:
Plaintiff’s amended, five-count complaint alleged strict product liability, negligence and breach of warranty against Weedhopper of Utah, Inc. (Weedhopper), and strict product liability against Lawrence Engineering, Inc. (Lawrence), and Hughes Aircraft Company, in seeking recovery for injuries he sustained in the crash of a Weedhopper ultralight aircraft which he had purchased and assembled. Weedhopper answered and filed affirmative defenses, to which plaintiff responded. Lawrence also answered. Thereafter, both Weedhopper and Lawrence filed motions for summary judgment. Subsequently, Weedhopper filed a petition in bankruptcy, and the action against it has been stayed. Hughes Aircraft Company was not involved in the incident complained of, was erroneously joined as a defendant and was voluntarily dismissed by the circuit court. Plaintiff answered Lawrence’s motion for summary judgment. After a hearing, the summary judgment motion was allowed, from which plaintiff appeals.
We are asked to decide whether summary judgment was properly granted where plaintiff presented circumstantial evidence rather than direct proof of Lawrence’s involvement in supplying a defective aircraft bolt to Weedhopper, which plaintiff claims was supplied to him in the kit purchased from Weedhopper, and which is alleged to have been a proximate cause of the accident and plaintiff’s injuries. For the reasons set forth below, we reverse and remand for trial.
Prior to filing for bankruptcy, Weedhopper was in the business of selling unassembled ultralight aircraft. Typically, when an order was placed with Weedhopper, its employee would gather the necessary parts into a kit which would then be sent to the customer. On August 13, 1979, plaintiff ordered a kit from Weedhopper. He received the kit on November 26, 1979, and completed assembly of the aircraft on June 6, 1980. Included in plaintiff’s kit, as with all Weedhopper kits, were various aircraft quality bolts, including one designated “AN433.” The bolts were manufactured by California Screw, Inc. (California), and distributed by Lawrence and by Hughes Aviation. California marks the heads to its bolts, but Hughes Aviation and Lawrence do not further distinguish the bolts that they distribute. Weedhopper received bolts from both Lawrence and Hughes Aviation and organized the bolts according to size, irrespective of supplier.
Between the assembly date, June 6, 1980, and the crash date, July 8, 1980, plaintiff flew his aircraft several times for a total flying time of approximately eight hours. He alleged that on July 8, 1980, an AN4-33 bolt sheared off, causing the aircraft to crash. Although the bolt’s head was never recovered, plaintiff’s expert, a metallurgist, examined the shaft of the bolt and concluded that its surface pitting and high concentration of hydrogen made it unsuitable for aircraft use. As a result of the crash, plaintiff suffered a concussion and fractured vertabrae, among other injuries, and was unable to work for about six months.
On December 30, 1980, this action against Weedhopper was filed sounding in strict product liability and negligence. Following receipt of answers to interrogatories, plaintiff amended his complaint adding a breach of warranty count against Weedhopper and adding Lawrence and Hughes Aircraft as defendants to strict product liability counts. The manufacturer, California Screw, was not joined as a defendant, plaintiff asserting he was not aware of its identity or even of its existence until after the limitations period had run. Weedhopper subsequently filed for bankruptcy and proceedings against it were stayed. Hughes Aircraft was misidentified; the intended defendant was Hughes Aviation. Following the voluntary dismissal of Hughes Aircraft, Hughes Aviation could not be joined due to the running of the limitations period. Plaintiff then proceeded only against Lawrence.
Lawrence’s motion for summary judgment asserted that plaintiff had failed to establish any link between it and the allegedly defective bolt. Susan Boman, president of Weedhopper, stated in an affidavit that there was no way she could positively determine from Weedhopper’s records or from the AN4-33 bolt itself who actually supplied the bolt that was shipped to plaintiff, a position also taken in her deposition, in which she stated that Hughes Aviation supplied bolts to Weedhopper in 1977 and 1978 when Weedhopper was first starting up, because, at that time, Hughes could supply the bolts necessary for the limited number of kits ordered and because Hughes was nearby. Boman’s deposition, excerpts of which were filed by plaintiff in opposition to Lawrence’s motion, revealed these further asserted facts: As orders increased, Weedhopper switched to Lawrence. During 1979 Weedhopper procured approximately 90% of its AN4-33 bolts from Lawrence, according to Boman. Hughes Aviation was then used only when bolts were needed immediately. Hughes Aviation was never a major wholesale supplier of aircraft parts, but was a small operation supplying parts at a private airport and apparently did not even publish a parts catalog. Hughes Aviation was used by Weedhopper because it was close by, allowing Weedhopper employees to pick up an occasional part as necessary. Hughes Aviation could not satisfy Weedhopper’s regular day-to-day demand by 1979; regular orders went to Lawrence. When plaintiff received his kit in November 1979, Weedhopper’s use of Hughes Aviation was limited to supplying its “proto-type department” and occasional individual backorders for insistent customers. Lawrence was Weedhopper’s “primary supplier” indicating that during 1979, the AN4-33 bolts in Weedhopper’s bin were probably supplied by Lawrence. Originally, plaintiff’s particular kit was missing bolts which were on backorder.
The ratio of AN4-33 bolts supplied to Weedhopper by Lawrence and by Hughes Aviation provided the basis for Lawrence’s motion for summary judgment. When asked what proportion of Weedhopper’s AN4-33 bolts were purchased from Lawrence and what proportion from Hughes Aviation, Boman replied: “I would probably put it at 90 to 10; 90 to Lawrence; 10 to Hughes [Aviation].” Plaintiff opposed Lawrence’s motion for summary judgment by arguing to the circuit court that the nine to one probability established a factual basis for a jury to permissibly infer circumstantially that Lawrence supplied the allegedly defective bolt. The circuit court, however, granted Lawrence’s motion, stating that nine to one odds could not provide the basis for a reasonable inference sufficient to present a jury question.
Summary judgment, although a salutary procedure in the administration of justice, must be granted with caution so that no party’s right to trial is usurped in the presence of conflicting facts and inferences or when reasonable persons might fairly reach differing results. (Aspegren v. Howmedica, Inc. (1984), 129 Ill. App. 3d 402, 404, 472 N.E.2d 822; Elliott v. Chicago Title Insurance Co. (1984), 123 Ill. App. 3d 226, 231, 462 N.E.2d 640.) Summary judgment should be granted only when the pleadings and other evidence demonstrate that there is no triable issue of material fact and that the movant is therefore entitled to judgment as a matter of law. (Ill. Rev. Stat. 1983, ch. 110, par. 2 — 1005; Aspegren v. Howmedica, Inc. (1984), 129 Ill. App. 3d 402, 472 N.E.2d 822; Elliott v. Chicago Title Insurance Co. (1984), 123 Ill. App. 3d 226, 462 N.E.2d 640.) The circuit court must determine whether a triable issue exists from the affidavits, depositions, admissions, exhibits and pleadings in the case. (Carruthers v. B.C. Christopher & Co. (1974), 57 Ill. 2d 376, 380, 313 N.E.2d 457.) The respondent need not prove his case at the summary-judgment stage, but he may be required to present some evidence which demonstrates the existence of a triable and genuine issue of fact. (Ralston v. Casanova (1984), 129 Ill. App. 3d 1050, 1059, 473 N.E.2d 444.) Inferences which may be reasonably drawn from the evidence are resolved in favor of the nonmovant. (Rubin v. City National Bank & Trust Co. (1980), 81 Ill. App. 3d 1020, 1022, 402 N.E.2d 281.) Where the evidence raises no issue of material fact, however, summary judgment is properly granted. Ralston v. Casanova (1984), 129 Ill. App. 3d 1050, 1056, 473 N.E.2d 444.
To recover under strict liability in tort, plaintiff must prove that: (1) injury resulted from the condition of the product; (2) the condition was unreasonably dangerous; and (3) the condition existed when the product left defendant’s control. (Suvada v. White Motor Co. (1965), 32 Ill. 2d 612, 621-22, 210 N.E.2d 182; Dunham v. Vaughan & Bushnell Manufacturing Co. (1969), 42 Ill. 2d 339, 342-44, 247 N.E.2d 401.) Further, it is necessary that defendant be in the business of placing the product in the stream of commerce. (Sismen v. Alden (1975), 34 Ill. App. 3d 961, 963, 341 N.E.2d 713.) It is apparent that liability rests upon defendant’s participation in the circumstances. (Keen v. Dominick’s Finer Foods, Inc. (1977), 49 Ill. App. 3d 480, 482, 364 N.E.2d 502.) In Illinois, a plaintiff must identify the supplier of the product and establish a causal relationship between the injury and the product. (Schmidt v. Archer Iron Works, Inc. (1970), 44 Ill. 2d 401, 402-03, 256 N.E.2d 6, cert, denied (1970), 398 U.S. 959, 26 L. Ed. 2d 544, 90 S. Ct. 2173.) Thus, in product liability cases, the supplier’s link to the product in question must be shown. Schmidt v. Archer Iron Works, Inc. (1970), 44 Ill. 2d 401, 405-06.
The parties here do not seriously dispute that the elements of a product liability action may be proved inferentially or by direct or circumstantial evidence. The dispute centers, instead, on whether the fact that Lawrence supplied 90% of the bolts used by Weedhopper is sufficient circumstantial evidence to avoid entry of summary judgment. Circumstantial evidence consists of facts or circumstances which give rise to a reasonable inference of the truth of an underlying fact. (Illinois Pattern Jury Instruction, Civil, No. 1.03 (2d ed. 1971).) Such evidence must have reasonable probative force; the jury will not be allowed to engage in conjecture, surmise or speculation. Rockett v. Chevrolet Motor Division, General Motors Corp. (1975), 31 Ill. App. 3d 217, 221, 334 N.E.2d 764.
The focus must then be on what quantum of evidence is sufficient for an inference to be reasonable. This measure has eluded specific standardization and enumeration. (Consolino v. Thompson (1984), 127 Ill. App. 3d 31, 33, 468 N.E.2d 422.) Generally, the test of reasonableness resolves itself into a question of probability: is the inferred occurrence more probable than not, or is it merely possible. Consolino v. Thompson (1984), 127 Ill. App. 3d 31, 33-34, quoting James, Sufficiency of the Evidence and Jury-Control Devices Available Before Verdict, 47 Va. L. Rev. 218, 221-22 (1961).
In the instant action there is evidence that: (1) Lawrence supplied 90% of Weedhopper’s AN4-33 bolts in 1979; (2) Lawrence was used by Weedhopper to supply bolts to meet general demand; and (3) Hughes Aviation was used to supply bolts only as specially necessary. This evidence, while circumstantial, permits the inference that the bolts in Weedhopper’s bin and the bolt supplied to Kramer were purchased from Lawrence. Hughes Aviation was merely a “possible” source of the bolt and plaintiff need not, at least at summary judgment stage, disprove that possibility. Evidence showing that defendant was the exclusive distributor of a product would strongly support plaintiff’s case when defendant’s identification can be proved only circumstantially; but when two suppliers of an allegedly dangerous product exist, under circumstances which show that a defendant supplied 90% of the parts used, this evidence is sufficient to withstand a motion for summary judgment.
The standard of proof in civil litigation is neither absolute nor beyond a reasonable doubt; here, a preponderance of the evidence will suffice. Defendant was allegedly the most probable cause of plaintiff’s injury. The defects in plaintiff’s proof are such that affect the weight which should be accorded the evidence, not whether the evidence initially poses a genuine material triable question of fact. To hold otherwise would require the granting of summary judgment whenever a defendant raises the mere'possibility of misidentification. A situation such as this, dealing with wholesale suppliers of fungible goods, may not allow for the direct identification of who supplied an allegedly defective part. Plaintiff, in the present posture of the instant action, has presented sufficient evidence to establish a strong inference that Lawrence supplied the allegedly defective bolt and he is entitled to develop his case at trial. Summary judgment, therefore, must be reversed and the cause remanded for trial.
Reversed and remanded.
BILANDIC, P.J., concurs.