Specific target organ toxicity is the ability of the substance or mixture to cause harm to particular organs of the body, such asthe blood, the liver or the nervous system, at doses below those which would cause more general toxicity. STOT effects may happenafter a single exposure, or after several repeated exposures. Specific target organ toxicity – single exposure (SE): the classification criteria for substances and mixtures are very similar in both the DSD/DPD and CLP.