As of now, a manufacturer can list '0%' trans fat per serving if the % is less than .5%. This is dangerous. Trans fats are harmful and they don't go away. They reside in the body, accumulating, like radiation doses. .49% is absolutely NOT '0'.
Also, packaging often says '0% trans fat per serving'. This is misleading, as the serving size can be made to create just that goal. I seldom see: 'Contains NO trans fat'.
Demand Congress &/or the FDA make ALL trans fats be revealed on nutrition labels...even to traces of .001% - all those %s add up and accumulate.
[NOTE: If this necessary labeling is enforced, be prepared to see labels like: 'Serving size: approx. 1 chip, Servings per container: approx. 225'.]