A report by the American Academy for the Advancement of Science has concluded that much of the currently uncontrolled dioxins to which North Americans are exposed comes from the incineration of wastes.
Dioxins are countable, as the OG notes :) Think of it this way: Water is not countable, but the elements that water comprises (oxygen molecules, hydrogen molecules) are countable. Dioxins are individual chemicals and thus are countable.
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