An efficient intervening cause is the new and independent act which itself is a proximate cause of an injury and which breaks the causal connection between the original wrong and the injury. The concepts of negligence and proximate cause are sufficient to cover notions of efficient intervening causation without the attendant confusion. Hence, the concept of efficient intervening cause is subsumed by the concepts of proximate cause and concurrent cause.
In Gerlach v. State, 9 Neb. App. 806 (Neb. Ct. App. 2000), the court held that “An efficient intervening cause is a new, independent force intervening between a defendant's negligent act and a plaintiff's injury by the negligence of a third person who had full control of the situation, whose negligence the defendant could not anticipate or contemplate, and whose negligence resulted directly in the plaintiff's injury. If, conversely, the third party's negligence is reasonably foreseeable, then the third party's negligence is not an efficient intervening cause as a matter of law. However, if a defendant's conduct constitutes merely passive negligence, which creates a condition which facilitates injury through subsequent third-party negligence, the third-party negligence is an efficient intervening cause. The question whether the negligence of a third person constitutes an intervening cause is a question of fact.”