A study of 73 male employees in a 2,4,5-T factory was made. Chloracne was found in 13 (18%) workers. Severity of chloracne correlated significantly with the presence of hyperpigmentation, hirsutism, eye irritation, and a high score on the manic scale of the Minnesota Multiphasic Personality Inventory. Chloracne was not, however, correlated significantly with job location within the plant, duration of employment, or coproporphyrin excretion. Although 11 subjects with uroporphyrinuria and at least three with overt porphyria cutanea tarda had been found in a study of the same plant six years ago, no clinical porphyria could be currently documented and only one worker had persistent uroporphyrinuria. Evidence of toxicity in other organ systems was markedly less than that reported in previous studies and could not be shown to differ from normal populations in most instances.