California, a chapter published in Implementing Institutional Controls at Brownfields and Other Contaminated Sites, discusses California's large number of brownfields sites due to its long industrial history. Currently, there are more than 100,000 brownfields sites in the state. Consistent with well-established brownfields laws, California's environmental agencies have authority to perform risk-based cleanup that allows for some residual contamination to remain on-site. If residual contamination is permitted to remain, the state's environmental agencies must implement engineering and institutional controls to protect human health and the integrity of the remedy. California's environmental agencies have implemented institutional controls at no fewer than 752 sites across the state.