State law preempts local legislation that duplicates, contradicts, or enters an area fully occupied by general law, either expressly or by legislative implication. Here, Monterey’s Measure Z which banned oil and gas wastewater injection and impoundment and the drilling of new oil and gas wells throughout the County’s unincorporated areas was preempted by Pub. Resources Code 3106 which delegates to the state’s oil and gas supervisor the authority to drilling, operation, and maintenance of oil and gas wells. Measure Z contradicts the authority section 3106 delegates by its absolute bans on certain extraction methods and on all new oil or gas wells in Monterey County.