After flood, floor of a factory became slippery as some oily substance got mixed with water. The owners of the factory (defendants) took steps to get rid of the effects of flood and spread all the sawdust available with them on floor. But some oily patches remained uncovered due to lack of further supply of sawdust. A, a worker in the factory (plaintiff), slipped from one of such oily patches. He sues the defendants for damages. Which of the following is correct?