Woodsmoke contains at least five chemical groups classified as known human
carcinogens by the International Agency for Research on Cancer (IARC), others
categorized by IARC as probable or possible human carcinogens, and at least 26
chemicals listed by the U.S. EPA as hazardous air pollutants.
(tijdschrift - Inhalation Toxicology: Woodsmoke health effects - a review (2007).pdf)
Er zitten dus minimaal 5 kankerverwekkende groepen stoffen in houtrook. Niet "waarschijnlijk kankerverwekkend", maar: "bekend als kankerverwekkend".