What characterizes List 1 chemicals in their relation to controlled substances?

List 1 chemicals are characterized by their status as essential precursors for the synthesis of certain controlled substances. This means that they are directly involved in the production of drugs that are regulated due to their potential for abuse and addiction. Recognizing the importance of these chemicals is crucial for regulatory purposes, as they can be used in the illicit manufacture of controlled substances, which calls for careful monitoring and control measures.

In contrast, the other options suggest characteristics that do not accurately reflect List 1 chemicals. For example, the notion that they are solely for industrial applications overlooks their role as precursors in drug synthesis. The claim that they are forbidden by law is misleading because many List 1 chemicals are legally regulated but not outright banned, as they have legitimate uses in pharmaceutical manufacturing under strict regulatory controls. Lastly, asserting that they have no practical applications ignores their essential role in both legal drug synthesis and various chemical processes in industries. Thus, identifying List 1 chemicals as vital precursors highlights their significance in the context of controlled substances.