The Los Angeles County Board of Supervisors Tuesday directed all departments to stop using a popular weed killer until more is known about its potential health and environmental effects.

Supervisor Kathryn Barger recommended the moratorium on glyphosate — a main ingredient in the herbicide brand Roundup.

“I am asking county departments to stop the use of this herbicide until public health and environmental professionals can determine if it’s safe for further use in L.A. County and explore alternative methods for vegetation management,” Barger said.

Roundup was developed decades ago by Monsanto Co., now owned by Bayer, and is believed to be the most widely used herbicide worldwide.

The motion, co-authored by Supervisor Sheila Kuehl, cites “a growing body of scientific study” of herbicide safety and the potential for negative impacts.

“In a 2015 study led by 17 experts from 11 countries, the World Health Organization’s International Agency for Research on Cancer concluded that glyphosate should be classified as ‘probably carcinogenic to humans,'” Kuehl said.