Corporate-backed efforts to limit the reach of California's Consumer Privacy Act through legislative amendments ran into a political buzzsaw Tuesday as a state Senate committee killed one key bill and handcuffed another that organized labor had opposed.

The author of a third bill that would have allowed certain sales of personal data to government agencies shelved the measure without a vote after the Senate Judiciary Committee issued a critical analysis of the legislation.

The demise of the bills over the course of a 12-hour committee hearing Tuesday marked the first significant defeat for tech companies, business groups and their lobbies, which have been trying to redefine aspects of the landmark data privacy law since its hasty passage last year. The law goes into effect in 2020.