I’ll be typing up my notes of the County’s news conference soon, but wanted to comment for now on the seemingly reassuring word that no traces of PCBs were found in the initial tests done today—despite there being, reportedly, a barrel of PCBs onsite.
It's no secret that when hazardous materials burn, especially at very high temperatures, their composition can change significantly. As the Canadian site linked below notes, when PCBs burn, they may become aerosolized and readily inhaled, and this might happen at some distance from the fire.
Worse, “when PCBs are burned at high temperatures, the process can turn them into different substances called dioxins and furans, which are far more toxic than PCBs.”
The audio on WGXC was very difficult to hear at least 50% of the time (a kingdom for a sound engineer!) but one answer that one could kind of make out was that officials have not gotten back the results for dioxins yet—maybe tomorrow, it was said.
There is obviously a reason why companies get paid a lot of money to dispose of PCBs, and why incinerators and landfills are supposed to be closely regulated and monitored. Incinerating even small quantities of PCBs or other hazardous substances in an uncontrolled warehouse fire is not exactly recommended practice, and not something one can be easily reassured about.