But much of the nearly four-hour hearing was focused on the causes of autism. And though mercury and vaccines have been ruled out as contributing factors by many in science and the media, questions about them dominated much of the afternoon.

The hearing, on Thursday, November 29, was convened by the House Government Oversight Committee, chaired by Darrell Issa (R-CA), one of President Obama's most vocal conservative critics. But it wasn't just the Republican majority demanding answers about mercury and vaccines. Some of Congress's most progressive Democrats, including Elijah Cummings (MD), Eleanor Holmes Norton (DC), John Tierney (MA), Carolyn Maloney (NY) and Dennis Kucinich (OH) also issued pointed queries.

Most members expressed deep frustration at the slow pace of federal autism research: Their constituents are complaining about the government's intensive focus on genetic issues over environmental factors.

It was, perhaps, one of the most bipartisan get-togethers Capitol Hill has witnessed in years. Republicans and Democrats calmly turned their sights on the federal policymakers, launching an unexpected barrage of questions about the impact of mercury on children, the intensity of the vaccine schedule, and the safety of simultaneously giving 6-9 immunizations to an infant.

Vaccines came up right away.

"Was there autism before there was vaccination?" Issa asked in opening the questioning of two federal witnesses: Alan Guttmacher, M.D., director of the National Institute of Child Health and Human Development and Coleen Boyle, Ph.D., director of the National Center on Birth Defects and Developmental Disabilities at the CDC.

Boyle said "definitely," and Guttmacher said there was "heavy suspicion," though neither could offer any evidence.

"Is it fair to say that we can rule nothing out?" Issa continued, asking about mercury in air pollution and the vaccine preservative thimerosal.

"It's always difficult in science to rule anything out as a possibility for occasional individuals," 
Guttmacher said, "but we can rule them out as being involved in the vast majority of individuals." Boyle noted that the Institute of Medicine had issued reports in 2004 and 2011 "suggesting that vaccines did not increase the risk."

But those assurances did nothing to stop the mercury and vaccine questions.

Rep. Dan Burton, (R-IN) a Tea Party member who is retiring this year, showed a video from the University of Calgary depicting the rapid disintegration of neurons following exposure to mere ions of mercury.

Burton noted that US autism rates had exploded from 1-in-10,000 to 1-in-88 and called it "worse than an epidemic; it's an absolute disaster. How can anyone at the CDC and FDA watch something like that and say that the mercury does not have an impact on neurological problems?"

Rep. Holmes Norton wanted a response to the video from the scientists at the table, but she didn't get one. The CDC's Boyle simply said that mercury had been removed from childhood vaccines in 2001 (not 1999, as widely reported) except for multi-dose flu vaccines.

Rep. Kucinich raised the issue of thimerosal, but said mercury from coal was also a likely culprit. In either case, he said, money in politics was impeding the search for autism's causes. "We're not only talking about drug manufacturers, we might be talking about coal companies too," he said.

Rep. Tierney asked the CDC's Boyle why thimerosal was taken out of childhood vaccines, except the flu shot, if there were no concerns about its safety profile, but she had no ready answer for him.

Many members wanted to know why children receive multiple shots at once.

"I've had so many parents write to me or come to me saying they had a healthy child who then got 10, 9, 6 vaccines at one time and that child changed overnight," Rep. Maloney said. "Why does the schedule require a child to receive so many vaccines in such a short period? I'm totally for (vaccines) but why do you have to cram 9, or 6, at a time when the verbal evidence seems so strong from so many people?"

The schedule was designed "to make sure everyone gets it," Boyle replied. "Not everybody goes to the doctor routinely, so they use that opportunity to make sure that happens."

Rep. Vern Buchanan (R-FL) countered that his constituents "feel strongly that this has to be looked at in a very, very aggressive way that, if we're over-vaccinating our children."

"We know vaccines save lives," Boyle responded. For each US birth cohort, vaccines saved 43,000 lives, prevented 20 million illnesses and saved $13.6 billion in medical costs, she said, without addressing the concerns of the members' constituents. Buchanan said autism costs are estimated at $137 billion annually: "We need to fix this problem because it's obviously out of control."

The conservative Buchanan was echoed by his equally liberal counterpart Rep. Cummings, the committee's ranking member, who delivered an impassioned soliloquy to the scientists.

"There's something wrong with this picture. When you've got this combination of shots, and you go from 1-in-10,000 to 1-in-88, it seems to me somebody would say, 'Wait a minute. Let's put the brakes on this,'" he said. "I wish you could see the people behind you. There are grown men crying behind you... Let's err on the side of keeping children safe, even if we have to do a pause and give children one shot per day."

Rep. Bill Posey (R-FL) grilled Boyle on a Danish scientist named Poul Thorsen, indicted for embezzling more than $1 million in CDC research funds and now the most-wanted fugitive at the Office of the Investigator General at HHS.

Thorsen was chief of a major research group, North Atlantic Neuro-Epidemiology Alliances (NANEA) founded in 2000 with a $7.8 million CDC grant and tasked with researching a number of disorders including autism, according to Danish news accounts.

"What steps has the CDC undertaken to ensure the integrity of the research that was performed by Dr. Thorsen?" Posey asked. Boyle said he was, "a co-investigator on a couple of studies that came out on autism. He was really just one investigator."

But had CDC gone back to validate the studies? "This guy is a humongous scumbag, one of the most wanted men on earth," Posey charged. "And you relied on him for data to determine if thimerosal had a negative effect?"

"Two studies don't conclude a body of work," Boyle replied.

Issa promised more hearings and suggested that the federal Interagency Autism Coordinating Committee should expect to testify soon. Meanwhile, he may help obtain CDC emails and other documents hitherto redacted that could shed light on the agency's alleged mishandling of thimerosal data, and its cozy relationship with Thorsen (more on that later).

Like many people, I thought the autism-mercury-vaccine discussion was essentially over. But clearly, it is not. And though many fretted that the controversy would drive fearful parents away from vaccination, the opposite it true: US rates remain at all-time highs.
Critics of the committee will say its members are mere politicians and we must listen to scientists. But when it comes to autism's causation, the scientists in the room that day had little to say.

Guttmacher didn't "know all the studies in the autism literature," but said he'd "be happy to look into them."

Below are 30 recent studies that support a potential role for environmental factors, including mercury and vaccines, that Guttmacher and the committee might want to read.