DNOC

Hazard Summary-Created in April 1992; Revised in January 2000

4,6-Dinitro-o-cresol (DNOC) was used as a pesticide until 1991. It is extremely toxic to humans. Symptoms of acute (short-term) and chronic (long-term) toxicity include profuse sweating, increased pulse and respiratory rates, thirst, fatigue, headache, appetite loss, and greenish-yellow pigmentation of the conjunctivae in humans. Bilateral cataracts and blindness have been observed in individuals chronically exposed to DNOC by ingestion. Effects to the respiratory, cardiovascular, gastrointestinal, and central nervous system (CNS) of chronically exposed workers have been reported. No information is available on the reproductive, developmental, or carcinogenic effects of DNOC in humans. EPA has not classified DNOC for potential carcinogenicity.

Please Note: The main source of information for this fact sheet is EPA's Health and Environmental Effects Profile for Dinitrocresols and the Agency for Toxic Substances and Disease Registry's (ATSDR's) Toxicological Profile for Dinitrocresols.

Uses

EPA cancelled DNOC's registration as a pesticide in 1991. (5)

DNOC was used as a dormant spray insecticide, especially for thinning the blossoms of fruit trees or to kill locusts. (1,5,7)

DNOC was also used as a contact herbicide for the control of broad-leaf weeds in cereals and for the pre-harvest desiccation of potatoes and leguminous seed crops. (1,5)

Sources and Potential Exposure

Workers may have been formerly exposed by inhalation or dermal contact during the manufacture, formulation, or application of the pesticide. (1,5)

DNOC may have been released to water in industrial effluents, by direct pesticidal applications, or by pesticide leaching or runoff. (1,5)

Assessing Personal Exposure

DNOC can be measured in the blood, urine, and tissues of exposed persons. (5)

Health Hazard Information

Acute Effects:

Increased basal metabolic rates have resulted in humans following acute and chronic exposures to DNOC. Symptoms of toxicity from acute exposure include profuse sweating, increased pulse rate, increased respiratory rate, thirst, fatigue, lethargy, headache, nausea, appetite loss, malaise, collapse, coma and greenish-yellow pigmentation of the conjunctivae in humans. Yellow coloring of the hands, nails, and hair may also result. (1,2,5)

Damage to the liver, kidney, and nervous system have been reported in humans following acute exposure. (2,5)

DNOC is an uncoupler of oxidative phosphorylation, which accounts for its extreme acute toxicity. (1)

Dermal contact may lead to local necrosis. (3,5)

Acute animal tests in rats, mice, rabbits, and guinea pigs have demonstrated DNOC to have extreme acute toxicity from oral exposure and high acute toxicity from dermal exposure. (4)

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