[smaudet]

How is it bunk? If, say, arsenic is part of your extraction process of a non-petroleum based chemical, how is that safe?

That may be the extreme example, but there are many processes that involve processing chemicals without any "petrochemicals" being involved...

[mrguyorama]

The answer to your question is that chemistry is a science and we know what we are doing.

Also, that arsenic is naturally occurring and our body can handle it.

If you have ever drank apple juice or eaten rice, you have consumed arsenic. If you grow rice in the dirt with zero pesticides, it will have arsenic in it. The FDA sets the limits at the parts per billion level.

The biological half life of inorganic arsenic in a human is about 4 days, which is why people generally don't die from eating a few apple seeds over their lifetime.

If you learn chemistry, you can learn how <Chemical whatever> can be part of your extraction process yet not be part of the final product. It's a standard part of chemistry. It's fallible though, which is why the processes used for chemicals that go into food often use different processes than versions of that chemical not meant for consumption, and they have stricter regulations on purity and contaminants.