MANILA — Gina Lopez, a former environmental activist who introduced a crackdown on Philippine mining companies after she was appointed the country’s environmental secretary in 2016, died on Monday. She was 65.

Her death, from multiple organ failure, was confirmed by the ABS-CBN Foundation, a social development group of which she was the longtime chairwoman.

Ms. Lopez landed the job of acting environment secretary when President Rodrigo Duterte came to power in 2016. She wasted no time in going after major mining companies that she said had flagrantly violated environmental laws.

She ordered 23 mines to shut down and several others to suspend operations, and canceled 75 lucrative contracts for mines that she said threatened watersheds.