Judge allows cancer claim in Roundup case

Evidence that Roundup weed killer can cause cancer seems ‘‘weak,’’ but experts can still make that claim at trial, a US judge ruled yesterday.

The decision by US District Judge Vince Chhabria in San Francisco allows hundreds of lawsuits against Roundup’s manufacturer, Monsanto, to move forward. The lawsuits by cancer victims and their families say the agrochemical giant long knew about Roundup’s cancer risk but failed to warn them.

Many government regulators have rejected a link between cancer and the active ingredient in Roundup — glyphosate. Monsanto has vehemently denied such a connection, saying hundreds of studies have established that glyphosate is safe.

Chhabria said the evidence, ‘‘viewed in its totality, seems too equivocal to support any firm conclusion that glyphosate causes’’ nonHodgkin’s lymphoma.

Still, the judge said he would not go as far as saying that three experts presented by attorneys for the cancer victims and their families presented ‘‘junk science’’ that should be excluded from trial.

Monsanto did not immediately have comment. The judge wanted to determine whether the science behind the claim that Roundup can cause nonHodgkin’s lymphoma had been properly tested and met other requirements to be considered valid.

Before issuing his ruling, Chhabria spent a week in March hearing duelling testimony from epidemiologists. He peppered them with questions about potential strengths and weaknesses of research on the cancer risk of glyphosate. –