These conclusions are based on the rejected patent application and the NYDEC Permit as well as an in depth background in pyrolysis and plastic recycling.
As far as back yard fires that are not always closely scrutinized by gov agencies, yes, you are correct. When it comes to constant monitoring of a process in a controlled environment it is a different story.
The concern should be there, it only takes 1 or 2 parts per million of some of the potential contaminates to begin a chain reaction. The potential to produce dangerous results is very high with even the smallest amount of certain contaminates in a pyrolysis process.