Generally, plaintiffs must prove that their injuries would not have happened, but for the action of the defendant. One notable exception is when multiple factors contribute to the injury. In these exceptional cases, the plaintiff must prove that the defendant’s act or omission was a substantial factor in bringing about the injury; the plaintiff need not meet the “but for” causation test.
Two Physicians Contributed to the Injury
The Texas Supreme Court applied this principle in Bustamante v. Ponte, a medical malpractice case. The evidence indicated that the negligence of two physicians caused the injury. Dr. Ponte argued that the plaintiff could not prove that but for Dr. Ponte’s negligence, the plaintiff would not have been injured, because the plaintiff could not negate other possible causes, including the other physician’s negligence. The Court ruled that the plaintiff did not need to establish that the injury would not have occurred, but for Dr. Ponte’s negligence. Rather, the plaintiff only needed to prove that Dr. Ponte’s negligence was a substantial factor in causing the injury. In reviewing the evidence in this light, the Court ruled that the plaintiff proved that Dr. Ponte’s negligence was a substantial factor in causing the injury.
Court Applied Principle Used in a Toxic Tort Case
In Bostic v. Georgia-Pacific, decided in 2014, the Texas Supreme Court discussed the same concept in a toxic tort case involving multiple sources of exposure. In Bostic, the court rejected the “but for” standard advocated by the defendant, but also rejected the plaintiff’s argument that proof of any exposure could support a jury finding of causation in multiple source cases. Instead, the Court applied the “substantial factor” test in this toxic tort case with multiple sources of exposure. In Bustamante, the Court referenced Bostic, and stated that the concept of substantial causation also applies in other multiple causation cases.
Substantial Factor Evidence in Multiple Causation Cases
The Court held in Bustamante that the plaintiff’s evidence of substantial causation was sufficient to prove that Dr. Ponte’s negligence, more likely than not, caused the plaintiff’s injury. The plaintiff did not need to prove that, but for Dr. Ponte’s negligence, the injury would not have occurred.
Bostic left unresolved key questions about the evidence needed to establish “substantial factor” causation, when multiple actors could have caused the injury. This decision may provide assistance to judges and lawyers, but multiple causation cases will continue to be a challenge.
For a copy of the Court’s opinion in Bustamante click here.