In the Steward v. American Lava Company case of 1909, the U.S Supreme Court was tasked with determining whether a patent for an invention could be invalidated due to prior use by another party who had not patented it. The plaintiff, Steward, alleged that his patent for a process of making insulators used in electrical devices was infringed upon by American Lava Company. However, the defendant argued that they were using this method before Steward's patent and hence it should be considered as "prior art", invalidating Stewart’s claim. The court ruled in favor of American Lava Company stating that if an invention has been in public use or on sale more than two years prior to filing for a patent application then such patents are deemed invalid under U.S law (specifically Section 4886 Rev Stat). This ruling upheld previous decisions which stated that any knowledge or use of an invention before its date is sufficient evidence against its novelty and originality required for obtaining a valid patent.

The dissenting opinion in the case of Steward v. American Lava Company argued that the plaintiff, who was injured while working on a machine at his place of employment, should have been allowed to sue for damages. The dissenting justices believed that the lower court erred in its decision to dismiss the case without allowing it to go before a jury. They contended that there were questions regarding whether or not safety precautions had been taken and if negligence could be proven on part of the employer. Furthermore, they disagreed with majority's interpretation of "assumption of risk" doctrine which suggested an employee assumes all risks inherent in their job when accepting employment; instead they asserted this doctrine shouldn't apply where employers fail to provide safe work environment or equipment necessary for performing tasks safely.