In terms of entertainment value, the Environmental Protection Agency had it all this week.

The agency held a four-day-long gathering of scientists aimed at the rather dry task of analyzing numerous research studies connected to cancer concerns swirling around a chemical called glyphosate. Glyphosate is the world's most widely used herbicide and is the key ingredient in Monsanto Co.'s Roundup brand. But along with the slicing and dicing of data came razor sharp debate, questions about chemical industry influence over regulators, and even a bit of theater as one group of environmental activists interrupted proceedings to break out in song. Their refrain? "Monsanto is the Devil. No Glyphosate."

The meetings brought together a roster of scientists with expertise in epidemiology, toxicology and related expertise to advise the EPA on whether or not the agency has properly determined that the weight of evidence indicates glyphosate is "not likely to be carcinogenic" to humans. The determination runs counter to the classification made in March 2015 by the International Agency for Research on Cancer (IARC), an arm of the World Health Organization. IARC said a review of scientific research shows that glyphosate is a "probable human carcinogen."

The EPA's determination is crucial on many fronts - Monsanto is currently defending itself against more than three dozen lawsuits claiming glyphosate-based Roundup gave people non-Hodgkin lymphoma (NHL), a type of blood cancer; both the EPA and the European Union are assessing re-registrations of glyphosate to determine if limits should be placed on the chemical; and Monsanto is attempting a $66 billion merger with German-based Bayer.

But while the EPA may have hoped for resounding support from the Scientific Advisory Panel (SAP) it assembled, from the outset of the meetings on Tuesday, concerns were raised by some of the experts about the quality of the EPA's analysis. Some scientists were concerned that the EPA was violating its own guidelines in discounting data from various studies that show positive associations between glyphosate and cancer. Several of the SAP members questioned why the EPA excluded some data that showed statistical significance, and wrote off some of the positive findings to mere chance.

Monique Perron, a scientist in the Health Effects Division of EPA's Office of Pesticide Programs, explained that "professional judgment" played a role in looking at the "weight of evidence" from various studies. The EPA looked at both published studies as well as unpublished studies conducted by industry players like Monsanto, according to Perron. The IARC review focused on published, peer-reviewed research.

The public comments portion of the agenda opened with an interesting twist as a representative from the Italy-based European Food Safety Authority and one from the German Federal Institute for Risk Assessment (BfR) took to the microphones to weigh in on their perceptions of glyphosate's safety. Both said their own assessments were largely in line with the EPA view, that glyphosate is not a cause of cancer.

The BfR, which is part of the Federal Ministry of Food and Agriculture in Germany, advised EFSA and drafted the report that EFSA issued in November 2015 that declared glyphosate was "unlikely to be carcinogenic." That report has been the subject of some controversy because the BfR relied on the advice of the Glyphosate Task Force, the consortium of chemical companies that includes Monsanto, when it did its evaluation.

The EPA did not invite either BfR or EFSA to travel to the United States to deliver the support for glyphosate safety, according to Steven Knott, the EPA official who oversaw the meeting logistics. The foreign scientists simply asked for the opportunity to appear, he said. Who invited them and/or arranged for their travel raised some eyebrows among onlookers.

Another element of the meetings that did more than raise a few eyebrows was the devotion of time given to industry presenters supportive of glyphosate versus representatives from non-profits or others who urged regulators to rein in use of glyphosate. Monsanto representatives were granted roughly 3-1/2 hours on Wednesday to make the case for glyphosate safety, and several other pro-glyphosate industry players were granted additional time as well. In comparison, most critics of glyphosate had comment periods that ranged from 5-15 minutes. Knott said speaking allotments were assigned based on how much time commentators asked for, but some glyphosate opponents said they were told they could not have more than a few minutes.

Monsanto used its time to present a defense of glyphosate's value to agriculture, to offer detailed explanations for why the IARC analysis was flawed, and to explain why the company believes a host of data points found in various studies should be discounted, and/or are not relevant. Company representatives also argued that glyphosate residues found in numerous urine tests were nothing to worry about, and actually helped show that the chemical does not bio-accumulate in the human body. They also said reports of glyphosate residues found in human breast milk were "implausible."

Groups concerned about glyphosate argued to the panel that the EPA was favoring industry studies over published literature, which is generally considered more authoritative, and was using flimsy protocols to shrug off statistical significance found in several studies.

Many of the participants from both sides of the debate spoke of a need for research on the safety of formulated products that have glyphosate as the active ingredient. The EPA evaluates only glyphosate and not the actual formulation in which it is applied, even though the formulations are increasingly being feared to be more potentially dangerous to human health than the active ingredient alone.

One particularly interesting story line that played out this week was the saga of Dr. Peter Infante, a nationally recognized epidemiologist who initially was invited and confirmed by EPA as one of the agency's scientific advisory panel members for the glyphosate meetings. The meetings were slated for Oct. 18-21 but CropLife America, which represents the interests of Monsanto and other agribusinesses, sent a letter to the EPA on Oct. 12 calling for Infante to be completely disqualified, saying he had "patent bias." Infante appeared to have impeccable credentials, having spent decades working for the Occupational Safety and Health Administration and the National Institute for Occupational Safety and Health specializing in the determination of cancer risks associated with toxic substances. But CropLife insisted Infante be thrown off the panel. One of its reasons: Infante would give more weight to independent research than the industry's own research.

The EPA did as the industry asked, but the ousting did not sit well with Infante, who had spent long hours studying the data EPA sent the panel members in advance. In part to defend his reputation, and also to offer his analysis, a somewhat disgruntled Infante showed up at the EPA meetings anyway, telling the SAP members there is "impressive evidence" of glyphosate ties to NHL that should not be ignored.

"There is clearly the evidence for the risk of non-Hodgkin lymphoma related to glyphosate exposure," Infante said in an interview after he addressed the panel. "Is it conclusive? No, I don't think so. But I think that EPA is concluding that there is no evidence. And that's exactly wrong, according to their own criteria." There is enough data to classify glyphosate as having "limited" evidence of carcinogenicity in humans," Infante said.

By the time the singing broke out, the room seemed ready for the distraction. The Rev. Billy Talen, who leads a group of self-proclaimed "earth-loving urban activists" that frequently use performance as protest, took his turn at the microphone. Talen told the SAP members of his group's concern about glyphosate applications made on playgrounds around the country and the danger this could pose to children.

"We're very aware of the cancers that come from, we believe, from glyphosates," he told the group.

Shortly after, Talen was warned his five minutes were up, and he and a small number of his followers started singing: "Monsanto is the devil. No glyphosate. Hey."

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Never a dull moment in this debate.