Aldehydes are highly toxic compounds that are known to be human carcinogens. Formaldehyde is toxic through inhalation and is a strong irritant. The TLV is 1 ppm in air. Acetaldehyde is toxic with narcotic effects. The TLV is 100 ppm in air and the IDLH is 10,000 ppm. Propionaldehyde is an irritant. The toxicity hazards of the aldehydes also vary from one compound to another. Care should be taken to determine the exact hazards of any given compound.