"You have provided the drug companies with a captive costumer list. With the threat if you don't do this we are not going to let your children go to school. There is something that severally needs to be changed about that program," said Dr. Haley.

We conclude our series by looking into Missouri's mercury law. Mercury-based thimerosal is still in a trace amount in some vaccines. Drug companies say the metal exists in very low quantities to preserve the vaccine.

Ashley Reynolds: "So at this level it is considered toxic."

Dr. Engley: "Absolutely toxic."

Ashley Reynolds: "So for the people that say...it is such a small amount."

Dr. Engley: "They don't know what they are talking about."

But Dr. Frank Engley a microbiologist who served on boards with the FDA, CDC, and EPA in the 70s and 80s says even a little mercury is too much.

"You got to remember our work showed that thimerosal is toxic down to one-hundredth of a mill microgram or 1/10th to 1/millionth of a gram. So, taking it all out-they are not taking it all out. The company will say, well we still have to have some in our production. They don't have to. This is just a cover. So they can say, Well there is just a little bit. There is absolutely no reason for having thimerosal there. Absolutely no reason," said Dr. Engley.

But the CDC and other research says a trace amount of thimerosal is safe. Leaving a problem for parents deciding on vaccines.

"I think the thing for everybody to keep in mind is there are always going to be conflicting studies. That is just the way science goes. No two studies are done exactly the same way. Look at studies done by major groups that have credibility." Said Dr. Judity Miles. "That are generally around university settings. And then to look to the established sources of pediatrics. I think that is about as much as us parents can do. Then just say okay I gotta believe somebody because you are always going to get Aunt Harriet, the neighbor down the street…the newspaper…you start to go crazy if you sort all of those things out."

"They are killing our children. And the point that I am trying to make is, I think it is thimerosal. It is my best guess. I cant think of anything else that would fit the bill of an environmental toxin that would increase in Hawaii, Alaska and California at the same time," said Dr. Haley. It is the only thing that fills that bill and it would fit all these bio-chemical effects we see in these children." 

We are one of the few states that has a mercury limit law. Our law says pregnant women or children under three years of age receiving an immunization shall not contain more than 1 microgram of mercury per .5 milliliter dose. We met up with Senator Norma Champion in Springfield who sponsored this bill which is now law. She says just because major studies don't show a link between mercury in vaccines and autism doesnt mean it isn't possible.

"Its sort of like when the studies went on and on about the connection between cigarettes and cancer. It was very hard to show more than an indirect possible effect not a cause and effect. And that is possibly what is going on in this day," said Champion.

Regardless where you fall, lawmakers say Missouri is on its way to being a mercury free state.

"I think we will be banning it. Frankly what I think we have done we will end up banning it anyway if you have to do it for young children and there is a wave of people who don't want it at all. They don't have to have it if they dont want it." said Champion. I think that they probably wont use it. Certainly not for children and maybe not for anybody."

We should also note mercury isn't the only item considered alarming to some, vaccines also contain formaldehyde and aluminum. But doctors say those materials pose far less risk to children than living unvaccinated in a world of possible polio, measles, and hepatitis. This concludes our series combating autism from within. We appreciate all the comments we are getting. Be sure to check out the series in February. We plan to do a special hour long show about autism and talk with the team who put together the series you have watched for the past month.