Arsenic in chicken feed

Arsanilic Acid (which contains arsenic) is still legal in Canada as an ingredient in poultry feed. Why????

See CFIA website [You must be registered and logged in to see this link.]

Also see below, re US use.
"Maryland has become the first state in the US to ban an arsenic additive in poultry feed. A law banning the use of Roxarsone is among new state laws taking effect from January 1st 2013.

Pfizer, which distributes Roxarsone, a chemical used to help the birds grow and fight parasites, stopped selling the chemical in July after a US Food and Drug Administration study found higher levels of inorganic arsenic in chicken treated with the additive than those that were not. Arsenic is a known carcinogen.

Opponents however, said that the measure wasn't needed because the company voluntarily suspended sales of the product.

The impact of the ban could be limited because industry leader Perdue Farms discontinued its use of Roxarsone in 2007, while the drug was withdrawn from the market last year by Pfizer."

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Well that is disturbing information.
Reading these kinds of reports makes me wonder again about switching to only home-grown feed mixes. I do buy some commercial feed such as chick starter for the babies and a protein/mineral supplement for the adults. The main part of their diet is made up of whole and coarsely ground grains and legumes we grow ourselves or buy locally.

But how do you know what is in those pellets you buy? I've heard a few other stories about pelleted feeds that makes me question the wisdom of feeding your animals something that contains unknown ingredients.
And another thing...how much useless filler is there in those pellets? I'm thinking there must be a percentage of ground up hulls and stuff that adds fiber but little else to their diet. IF so, its a pretty expensive way to add fiber!

I followed it up with our feed supplier here, who contacted the manufacturer, who assured him there was no arsenic in their company's feed. Still, I like to see things in print.
I just wonder why it's legal at all. . . it seems like a total no-brainer to me that we shouldn't feed our food animals (or any others, for that matter) arsenic.