FILE - Containers of Roundup are displayed on a store shelf in San Francisco, Feb. 24, 2019.
FILE - Containers of Roundup are displayed on a store shelf in San Francisco, Feb. 24, 2019.

For the third time in less than a year, a jury has ruled the main ingredient in a popular weed killer caused cancer in its users.

A San Francisco jury Monday awarded more than $2 billion to a couple in their 70s who say glyphosate in Roundup weed killer gave them non-Hodgkin lymphoma.

The couple say they used Roundup for 35 years.

Attorneys for the couple say numerous scientific studies show glyphosate led to cancer in both animal and human populations.

The World Health Organization has classified glyphosate as "probably carcinogenic to humans" and last month, Vietnam said it would stop importing Roundup and other weed killers with the ingredient.

Bayer, Roundup’s manufacturer, argued that hundreds of other scientific tests show glyphosate is safe and that the U.S. Environmental Protection Agency determined that when used as directed, glyphosate is not dangerous.

Bayer says it is disappointed by Monday's verdict and plans to appeal. 

Two other juries in March and last August awarded multimillion-dollar settlements to Roundup victims, and thousands of other cases are pending against the company.

The Wall Street Journal reports the price of shares in Bayer has dropped 30% since its first courtroom defeat in August. The newspaper also says shareholders are angered the German-based company bought Monsanto last year when it sells a product suspected of causing cancer.