Due to the omnipresence of dioxins, all people have background exposure and a certain level of dioxins in the body, leading to the so-called body burden.
But it continues to raise concerns because there are no figures for dioxins - the toxins released during the burning of plastic and other synthetic materials.
More than 90% of human exposure to dioxins is through the food supply, mainly meat and dairy products, fish and shellfish.
As there was no evidence that hazardous waste was buried at the mine, investigators speculate that the source of dioxins may be natural, perhaps due to a prehistoric forest fire.
Incinerated materials containing chlorine can generate dioxins and furans2, which are human carcinogens and have been associated with a range of adverse health effects.
This level is the amount of dioxins that can be ingested over lifetime without detectable health effects.