University of Missouri biology professor Frederick vom Saal has been sounding the alarm about bisphenol A for a decade. Has he got your attention?

But industry-funded studies kept insisting that bisphenol A was safe.

In 2003, Welshons and vom Saal traveled to an international toxicology symposium in Germany, at the University of Berlin, where scientists from around the world were presenting papers on their research. Many of the papers presented were on bisphenol A.

A scientist named Jörg Oehlmann showed how bisphenol A in snails caused such an overgrowth in ovarian cells that the animals exploded and died.

A study by Gilbert Schönfelder found amounts of bisphenol A in human blood, specifically in the blood of pregnant mothers and in the placenta and umbilical-cord blood of their babies.

Then Waechter, the scientist with Dow Chemical who had visited vom Saal's lab at MU, stood up and read the results of a study he'd co-written. The study, which contradicted Schönfelder's, insisted that humans aren't exposed to bisphenol A because they metabolize it completely in the liver. His findings had come from cultures he'd done with liver cells in petri dishes, not living animals.

"It was at that point that you went a little ballistic," vom Saal says with a giggle, looking at Welshons.

Welshons says he stood up in the auditorium in Berlin and challenged Waechter's facts.

"I was civil," Welshons says. "I asked questions like: 'On what basis do you accept this C-R-A-P instead of actual measurements from animals and people? What basis is there for that?' And he ran away."

"Waechter literally stopped taking questions and ran out of the room," vom Saal says. "We're in this big corridor, and Wade jumps up and runs after him, and he's yelling, 'Come back here! Come back here and answer this question!' And Waechter ran out of the building with everybody in the audience sitting there."

Other scientists at the meeting don't remember it this way. Oehlmann, the scientist who did the snail study, writes in an e-mail, "I attended that meeting in Berlin in 2003 but do not remember a person leaving the room after being asked a particular question." Ellen Silbergeld, a professor of environmental health sciences at Johns Hopkins University who attended the Berlin symposium, says via e-mail: "There were several heated discussions at the meeting, but I do not recall anything like this."

Waechter wasn't available for comment. But Walton, Dow Chemical's spokesman, explains Waechter's behavior in an e-mail: Walton says that, according to Waechter, the confrontation happened on a stairway outside the meeting hall. "Dr. Waechter said that he told Dr. Welshons that he had a telephone call he needed to make at that moment and that he would not be able to have that discussion then, and that he then proceeded to his hotel room to make his telephone call. Dr. Waechter said the entire discussion took only a few seconds," Walton writes.

In 2004, vom Saal and another endocrinologist, Claude Hughes, conducted a review of the 115 published studies on bisphenol A and concluded that 90 percent of government studies found adverse low-dose effects, but not a single industry-funded study found any effect.

"Honesty in industry is not a requirement," vom Saal says. "As a matter of fact, the willingness to be dishonest seems to be the criterion for these people being hired and representing the chemical industry. We're playing on a very uneven playing field when we talk to them."

Welshons nods. "They can lie, and we can't."

Concern over chemicals such as bisphenol A eventually came to the attention of the government agencies charged with protecting public health. However, vom Saal and his fellow researchers have watched in disgust as federal agencies repeatedly fumble their responses.

The Environmental Protection Agency was supposed to be doing something about bisphenol A more than ten years ago.

In 1996, Congress passed the Food Quality Protection Act and the Safe Drinking Water Act, mandating that by 2000 the EPA was to begin protecting consumers from endocrine-disrupting chemicals such as those used in pesticides and plastics.

Scientists don't know how many of the 80,000 federally registered chemicals act as hormone disruptors. This year, the EPA was to have begun screening the first round of 50 to 100 chemicals. The tests haven't started yet.

The delay is partly because the EPA rounded up panels of experts to evaluate the process. Scientists were invited, but so were representatives of the chemical industry. Not surprisingly, consensus was hard to come by.

Five EPA panels have met to advise the EPA on chemical screening. Nagel was invited to be part of the second EPA panel for the Endocrine Disruptor Screening Program from 2001-03. She listened in frustration as fellow panelists dismissed the importance of measuring low-dose effects of hormones such as bisphenol A and failed to recognize the distinction between testing the chemicals on fetal animals versus adult animals.