Chelating agents to treat autism?

A potential study is under ethics review that would test chelating agents on children with autism. The reasoning is that the agents will remove mercury and prevent autism, because some parents are convinced that mercury in vaccines causes autism. This, by the way, has been discredited by much research, and most children have no heavy metal detected in their blood. But what are these "chelating agents"? And why would they even be considered? Well, chelating agents are compounds that bind to other elements - such as calcium, magnesium, mercury, iron - and help the body remove them. The chemical that would be studied, DMSA, is used to treat individuals with heavy metal poisoning. They want to test it in autistic children that have detectable levels of mercury in their blood. The problem though is that this could expose them to medical problems with no medical gain. The level in their blood is not even near the levels of poisoning. I would also like to add that fish, such as tuna, have high levels of mercury. Current environmental laws in the United States are a rollback of previous allowances so there is more now than previously. Pregnant women should limit their consumption. Also, mercury-based preservatives have been removed from pediatric vaccines. Any mercury that children have in their system now is due to environmental exposure, not vaccines. There is also no known neurological mechanism for mercury to cause Autism. So would chelating agents be worth researching - I don't think so. It is wasting time on a mechanism already shown to be uninvolved and it could make the kids more ill.