Another example is from Whorf's experience as a chemical engineer working for an insurance company as a fire inspector. While inspecting a chemical plant he observed that the plant had two storage rooms for gasoline barrels, one for the full barrels and one for the empty ones. He further noticed that while no employees smoked cigarettes in the room for full barrels, no-one minded smoking in the room with empty barrels, although this was potentially much more dangerous because of the highly flammable vapors still in the barrels. He concluded that the use of the word "empty" in connection to the barrels had led the workers to unconsciously regard them as harmless, although consciously they were probably aware of the risk of explosion. This example was later criticized by Lenneberg as not actually demonstrating causality between the use of the word "empty" and the action of smoking, but instead was an example of circular reasoning. Pinker in "The Language Instinct" ridiculed this example, claiming that this was a failing of human insight rather than language.