Description

Chlorothalonil is an organochlorine fungicide widely used to control fungal diseases on vegetables, trees, small fruits, peanuts, lawns and golf courses, ornamental plants such as roses, and to control fruit rot in cranberry bogs. Chlorothalonil is also added to some paints, stains, and wood preservatives to provide mildew resistance.

Products containing chlorothalonil are prohibited for use on home lawns, and products that contain chlorothalonil for mildew destruction must be labeled to prevent sale at over-the-counter retail outlets.

Children may be exposed to chlorothalonil during and after application of chlorothalonil-containing pesticides by neighboring facilities.

Health Effects

Immediate Health Effects

If SWALLOWED, chlorothalonil is Slightly Toxic
If ABSORBED THROUGH SKIN, chlorothalonil is Moderately Toxic
If INHALED (SNIFFED OR BREATHED IN), chlorothalonil is Not Available

Longterm or Delayed Health Effects

Allergen
Probably Carcinogen
Can damage DNA leading to mutations or cancer

Other

In tested rodents, high doses of chlorothalonil has caused tumors (benign and malignant) in the kidney.
Some formulations can cause severe eye and skin irritation, allergic dermatitis (skin rash), respiratory irritation, or allergic asthma upon contact.
Very high doses in laboratory animals have caused a loss of muscle coordination, rapid breathing, nose bleeding, vomiting, hyperactivity, dermatitis, vaginal bleeding, bright yellow and/or bloody urine, and kidney tumors.
In laboratory animals, chlorothalonil caused kidney damage, mild anemia, liver damage, embryo loss during pregnancy, DNA damage, and cancers of the kidney and forestomach.
Chronic skin contact can cause dermatitis, skin sensitization, and sensitivity to light. Swelling and inflammation of upper eyelids has been reported among workers.

How Exposures Occur

Ingestion From Eating Food

Traces of chlorothalonil have been detected on tomatoes, spinach, green beans, celery, apples, green peppers, peaches, pears, raspberries, strawberries, winter squash, and imported grapes and cantaloupes, among other produce.

Inhalation

Children can inhale chlorothalonil during spraying or when spray drifts from neighboring farms, golf courses, or lawns (although use on home lawns is now prohibited).

Children may also inhale particles of the pesticide when lying or playing on carpets, where pesticides can collect after being tracked indoors on shoes.

Ingestion From Soil

Chlorothalonil may remain in soil up to several months after treatment. Children living near agricultural areas where chlorothalonil is used could possibly be exposed by touching treated soil and putting their fingers in their mouth afterwards.

Occupational

Children of farm workers and pesticide applicators are exposed to higher amounts of chlorothalonil and other pesticides, which can enter the home on clothing, shoes, etc.

Significant Statistics

Chlorothalonil is the second only to sulfer in its use as an agriculture fungicide in the U.S.

Cox, Caroline. Fungicide Fact Sheet: Chlorothalonil, Journal of Pesticide Reform, Vol. 17, No. 4 (Winter 1997).http://www.pesticide.org/chlorothalonil.pdf

Chlorothalonil is very toxic to fish. Concentrations as low as 2 parts per billion can cause gill damage and anemia. It is also toxic to shrimp, frogs, beneficial microorganisms and earthworms. In plants it causes a variety of effects, including reductions in yield.

Cox, Caroline. ”Fungicide Fact Sheet: Chlorothalonil,” Journal of Pesticide Reform, Vol. 17, No. 4 (Winter 1997).http://www.pesticide.org/chlorothalonil.pdf.

Chlorothalonil is used most frequently on peanuts at 34% of chlorothalonil use in the US. Potatoes received about 12% of all chlorothalonil applications and tomatoes receive about 7%.

Reregistration Eligibility Decision: Chlorothalonil List A Case 0097. US Environmental Protection Agency. April 1999. http://www.epa.gov/oppsrrd1/REDs/0097red.pdf.

Solutions

How to detect chlorothalonil

Read labels on paints, stains and pesticides and avoid those containing chlorothalonil. They should not be used in homes. A search for chlorothalonil in the National Library of Medicine’s Household Products Database will show a list of brands that contain it.
Request Material Safety Data Sheets from your lawn care professional before use of pesticide products around your home. Do not permit use of chlorothalonil on your lawn or garden.

You can also find out if chlorothalonil is an ingredient in a pesticide product on Pesticide Action Network Pesticides Database.
Food: There is no way for parents to determine exactly how much chlorothalonil may be in their children’s food. You can get a rough idea of the fruits and vegetables that may contain chlorothalonil from:

The Environmental Working Group’s Report Card: Pesticides in Produce

How to minimize exposure to chlorothalonil

If you have any products containing chlorothalonil for home lawn usage or control of mildew, return it to the retailer or manufacturer, or contact your local sanitation department or hazardous waste disposal program to find out how to dispose of it properly. Earth 911 lists hazardous waste disposal sites by zip code.
To avoid tracking pesticides into the house, where they can become embedded in carpets, always remove shoes at the door or wipe shoes on door mats before entering your home.

Alternatives

Adopt Integrated Pest Management practices to keep fungal diseases at bay. Methods include keeping enough distance between plants and picking off diseased leaves to prevent the spread of the disease. For nontoxic treatments against rose diseases, which are often treated with chlorothalonil, see Pesticide-free Techniques for Managing Common Rose Diseases.
Buy certified organic foods, which are grown without synthetic pesticides. See 10 Fruits and Vegetables to Buy Organic.
Choose low-or no-VOC paints and stains. These paints are formulated to release fewer fumes. Natural paints, such as milk paints or plant- and mineral-based paints, may not contain toxic fungicides. Check the label before purchasing or contact manufacturers for more information.

For More information

Books, articles, factsheets and reports

Cox, Caroline. “Pesticide-free Techniques for Managing Common Rose Diseases,” Journal of Pesticide Reform, Vol 24, No. 2 (Summer 2004). http://www.pesticide.org/roses.pdf.

Cox, Caroline. ”Fungicide Fact Sheet: Chlorothalonil,” Journal of Pesticide Reform, Vol. 17, No. 4 (Winter 1997).http://www.pesticide.org/chlorothalonil.pdf.

Other government agencies

U.S. Environmental Protection Agency

Office of Pesticide Programs (Division Mail Code)
Ariel Rios Building
1200 Pennsylvania Ave. NW
Washington DC 20460

http://www.epa.gov/pesticides