LIHUE — A U.S. judge gave the green light to lawsuits alleging the weed killer Roundup caused cancer Tuesday, allowing expert testimony linking the herbicide to non-Hodgkin’s lymphoma.

U.S. District Judge Vince Chhabria said evidence that the active ingredient in Roundup — glyphosate — can cause the disease seemed “rather weak,” according to the Associated Press.

Still, the opinions of three experts linking glyphosate and non-Hodgkin’s lymphoma were not “junk science” that should be excluded from a trial, the judge ruled.

Lawsuits allege the agrochemical company and Roundup-maker Monsanto knows about the cancer risk and has failed to warn consumers.

Monsanto says the safety of the pesticide has been extensively tested and “the overwhelming conclusion of experts worldwide, including the EPA (Environmental Protection Agency), has been that glyphosate can be used safely according to label instructions.”

“Like all pesticides, glyphosate is routinely reviewed by regulatory authorities to ensure it can be used safely,” Montsanto said in a statement.

The company maintains the creation of glyphosate has been a “breakthrough for farming,” allowing another tool for farmers in their fight against weeds.

In response to Chhabria’s ruling, Monsanto Vice President Scott Partridge noted the judge excluded some of the plaintiffs’ experts and called the opinions of those he is allowing to testify “shaky.”

“Moving forward, we will continue to defend these lawsuits with robust evidence that proves there is absolutely no connection between glyphosate and cancer,” Partridge said in a statement. “We have sympathy for anyone suffering from cancer, but the science clearly shows that glyphosate was not the cause.”

Chhabria’s ruling allows the claims to move forward, though the judge warned it could be a “daunting challenge” to convince him to allow a jury to hear testimony that glyphosate was responsible for individual cancer diagnoses, according to AP.

The connection between pesticides and cancer has been a conversation on Kauai as well, and in 2016 a Joint-Fact-Finding study was competed on genetically modified agricultural production and pesticide use on Kauai.

The goal was to sort out facts about the industry’s impacts on Kauai, including health impacts to spraying pesticides around schools and the possibility the practice causes cancer to residents.

After a year of research, not enough information could be found to undeniably tie pesticide use to declining health in the surrounding community, but some recommendations were used in forming Hawaii’s new statewide ban of a different chemical — chlorpyrifos.

That ban starts Jan. 1 and with the passage of the law, Hawaii became the first in the nation to ban the pesticide due to linked health risks to surrounding communities where it is used.

The Hawaii Crop Improvement Association said Tuesday their members are still waiting for instruction from the state on how to proceed with the pending ban and new law.

Both County of Kauai and the State of Hawaii also use Roundup to control weeds.

Supporters of the chlorpyrifos ban on Kauai say they’re encouraged by the Chhabria’s decision to allow the cancer allegations to move forward because it’s indicative of a trend of more careful pesticide regulation.

“Who knows from my far corner of the world whether glyphosate causes non-Hodgkin’s lymphoma,” said Cynthia Welti, Wailua resident. “What we can know is we’ve had a long history in this country being cavalier about chemicals.”

She said Hawaii’s chlorpyrifos ban and the movement on the glyphosate cancer lawsuits means the U.S. is starting to understand potential serious dangers of using the chemicals.

“We’re in a long arc, and I see this ruling in California as part of this arc of getting more cautious,” she said.

She also pointed out Roundup and other glyphosate-containing chemicals do the job and it is a convenient go-to for people dealing with weeds like guinea grass.

“If you’re struggling with acres of guinea grass, it’s a strong tool that does the job,” she said. “But, I believe glyphosate is harmful to people. It’s in our honey and it’s pervasive.”

Monsanto is facing hundreds of lawsuits in state and federal courts concerning the chemical and Chhabria is presiding over more than 400 of them.

•••

Jessica Else, environment reporter, can be reached at 245-0452 or at jelse@thegardenisland.com. Associated Press contributed to this report.