“California, for example, passed a law in 1986 requiring food processors to warn consumers about any food containing carcinogenic chemicals. Processors and grocers are not asking the state to change its mind; they are trying to get Congress to pass legislation preempting all such state laws.”—David Rapp, October 1990
Answer
Answer:
This is an example of federal preemption. Under the Supremacy Clause, a valid federal law takes precedence over conflicting state laws, so Congress could preempt state food-warning laws by passing federal legislation.