Several experts have expressed serious concerns over the establishment of new pyrolysis plants in Denmark, particularly in light of reports from residents experiencing adverse health effects such as rashes, dizziness, and headaches following the construction of the world's largest pyrolysis plant in Smidstrup, south of Hjørring. The Danish Ministry of Climate anticipates the potential for 70 pyrolysis plants in the country by 2035, prompting significant debate about the need for precautionary measures before further permits are issued.

Philippe Grandjean, a professor of environmental medicine at the University of Southern Denmark, argues that the precautionary principle should be strictly adhered to, which necessitates waiting for comprehensive results from the Smidstrup facility before allowing any additional pyrolysis plants to be constructed. This caution is echoed by Erik Arvin, an emeritus professor from the Technical University of Denmark, and Lone Mikkelsen, a senior advisor from the Council for Green Transition, who emphasize the importance of understanding the impacts of these facilities on both health and the environment.

The pyrolysis process produces biochar as a byproduct, which is often touted as environmentally beneficial. However, the current concerns raised by local residents highlight the urgent need for a thorough evaluation of the health implications associated with these plants. The ongoing discussions and expert warnings signal a critical juncture in the approval process for pyrolysis technology in Denmark, where public health and environmental safety must take precedence over rapid industrial development.