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Public Health Statement for Tribufos

Public Comment Period Ends on October 30, 2018

CAS#: 78-48-8

Public Health Statement PDF PDF Version, 153 KB

This Public Health Statement is the summary chapter from the Toxicological Profile for Tribufos . It is one in a series of Public Health Statements about hazardous substances and their health effects. A shorter version, the ToxFAQs™, is also available. This information is important because this substance may harm you. The effects of exposure to any hazardous substance depend on the dose, the duration, how you are exposed, personal traits and habits, and whether other chemicals are present. For more information, call the ATSDR Information Center at 1-888-422-8737.

This Public Health Statement summarizes the Agency for Toxic Substances and Disease Registry’s (ATSDR) findings on tribufos, including chemical characteristics, exposure risks, possible health effects from exposure, and ways to limit exposure.

The U.S. Environmental Protection Agency (EPA) identifies the most serious hazardous waste sites in the nation. These sites make up the National Priorities List (NPL) and are sites targeted for long-term federal clean-up activities. The EPA has found tribufos in at least 4 of the 1,832 current or former NPL sites. The total number of NPL sites evaluated for tribufos is not known. But the possibility remains that as more sites are evaluated, the sites where tribufos is found may increase. This information is important because these future sites may be sources of exposure, and exposure to tribufos may be harmful.

If you are exposed to tribufos, many factors determine whether you’ll be harmed. These include how much you are exposed to (dose), how long you are exposed (duration), how often you are exposed (frequency), and how you are exposed (route of exposure). You must also consider the other chemicals you are exposed to and your age, sex, diet, family traits, lifestyle, and state of health.

What is Tribufos?

Tribufos is a colorless to pale yellow liquid with a skunk-like odor; it is used only as a defoliant (a chemical that removes leaves) for cotton plants. Removing the leaves keeps certain pests that may be found on the leaves from damaging the cotton before it is picked.

What happens to tribufos when it enters the environment?

When tribufos is sprayed onto cotton crops in cotton-growing states such as California, Texas, Mississippi, Louisiana, and Georgia, some of it may be found in the air at or near treated fields and in nearby water or soil. Tribufos does not travel long distances in air. Half of the tribufos that enters the air will break down within 2 hours. Therefore, people who live in states where cotton is not grown are not expected to be exposed to it from the air. Tribufos is not expected to move from soil to groundwater. We do not know how long tribufos will remain in soil, but we do know that it is slow to break down.

Tribufos does not readily move from soil or water to air. Tribufos does not become more concentrated in aquatic organisms than the concentration in the water where they live

How might I be exposed to tribufos?

Most people will not be exposed to tribufos unless they live near an area where tribufos is used to defoliate cotton plants. Tribufos is not for residential use or other non-occupational uses. Some cottoncontaining products such as cottonseed oil and cottonseed meal may contain very low amounts of tribufos, and you could possibly be exposed to it if you use these products for cooking. You may also be exposed to tribufos if you consume meat or milk from livestock fed tribufos-containing cottonseed products.

How can tribufos enter and leave my body?

If you were to breathe air containing tribufos, it could enter your blood through your lungs. Tribufos could rapidly enter your blood if you were to eat food or drink water containing tribufos. However, it is not likely that you would come into contact with food or water containing tribufos. Tribufos can be absorbed through the skin. Once in the body, tribufos is rapidly broken down and eliminated from the body within 1–3 days, mainly in the urine. Tribufos has not been shown to accumulate in any particular body organ or tissue.

How can tribufos affect my health?

Most people are not likely to be exposed to levels of tribufos high enough to cause signs and symptoms of acute toxicity. In the unlikely event that you were to be exposed to very high levels of tribufos, you might experience include excessive sweating, very small pupils, diarrhea, drowsiness, unconsciousness, and difficulty with breathing. You might also experience tearing of the eyes, runny nose, diarrhea, nausea, vomiting, loss of bladder control, and loss of muscle control. These effects would likely occur within a few minutes to 24 hours after high-level exposure, depending upon the extent and route of exposure. It is not known whether long-term exposure to low levels of tribufos might cause harmful effects in humans, including cancer. EPA evaluated results from carcinogenicity studies of rats and mice. There was no evidence of tribufos-related cancer in the rats. Tumors of the small intestine, liver, and lungs were reported in mice that were fed tribufos in the diet for nearly 2 years at levels many times higher than levels allowed in human food sources. Based on the results from the mouse study, a special EPA committee concluded that tribufos should be considered unlikely to be carcinogenic at low doses, but likely to be carcinogenic at high doses. The EPA committee concluded that human exposure to tribufos would not approach the dose level associated with tumors in the tribufos-treated mice.

How can tribufos affect children?

This section discusses potential health effects of tribufos exposure in humans from when they’re first conceived to 18 years of age.

We do not know whether children would be more sensitive than adults to tribufos toxicity. We do not know whether exposure to tribufos might cause birth defects or other developmental effects in people. Levels of exposure to tribufos high enough to affect the health of pregnant rats caused decreased numbers of rats born and decreased survival. These exposure levels were many times higher than levels allowed in human food sources.

How can families reduce the risk of exposure to tribufos?

If your doctor finds that you have been exposed to significant amounts of tribufos, ask whether your children might also be exposed. Your doctor might need to ask your state health department to investigate. You may also contact the state or local health department with health concerns.

People who live near agricultural areas where tribufos is used should stay away from the treated area. Air currents and water runoff can spread tribufos. If you are aware that tribufos is being sprayed, you may want to go indoors during spraying and stay there for a few hours after spraying is complete. Agricultural workers who come into contact with tribufos should consider changing work clothes before entering the home and washing work clothes separately from other family clothing

Is there a medical test to determine whether I have been exposed to tribufos?

There are no reliable medical tests to determine whether you have been exposed to tribufos. If exposure to tribufos is suspected, your doctor may request testing to determine the activity of the enzymes butyrylcholinesterase (BuChE) and/or acetylcholinesterase (AChE) in your blood. Your doctor may also need to check your red blood cell and hemoglobin levels because low levels of these blood elements could cause lower-than-normal activity of AChE in your blood.

What recommendations has the federal government made to protect human health?

The federal government develops regulations and recommendations to protect public health. Regulations can be enforced by law. Federal agencies that develop regulations for toxic substances include the Environmental Protection Agency (EPA), the Occupational Safety and Health Administration (OSHA), and the Food and Drug Administration (FDA). Recommendations provide valuable guidelines to protect public health but are not enforceable by law. Federal organizations that develop recommendations for toxic substances include the Agency for Toxic Substances and Disease Registry (ATSDR) and the National Institute for Occupational Safety and Health (NIOSH).

Regulations and recommendations can be expressed as “not-to-exceed” levels; that is, levels of a toxic substance in air, water, soil, or food that do not exceed a critical value usually based on levels that affect animals; levels are then adjusted to help protect humans. Sometimes these not-to-exceed levels differ among federal organizations. Different organizations use different exposure times (e.g., an 8-hour workday or a 24-hour day), different animal studies, or emphasize some factors over others, depending on their mission.

Recommendations and regulations are also updated periodically as more information becomes available. For the most current information, check with the federal agency or organization that issued the regulation or recommendation.


Agency for Toxic Substances and Disease Registry (ATSDR). 2018. Toxicological profile for S,S,S-Tributyl Phosphorotrithioate (Draft for Public Comment). Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service.

Where can I get more information?

If you have questions or concerns, please contact your community or state health or environmental quality department or:

For more information, contact:
Agency for Toxic Substances and Disease Registry
Division of Toxicology and Human Health Sciences
1600 Clifton Road NE, Mailstop S102-1
Atlanta, GA 30333
Phone: 1-800-CDC-INFO · 888-232-6348 (TTY)
Email: Contact CDC-INFO

ATSDR can also tell you the location of occupational and environmental health clinics. These clinics specialize in recognizing, evaluating, and treating illnesses resulting from exposure to hazardous substances.

Contact Us:
  • Agency for Toxic Substances and Disease Registry
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    Atlanta, GA 30341
  • 800-CDC-INFO
    TTY: (888) 232-6348
  • New Hours of Operation
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    Closed Holidays
    Contact CDC-INFO The U.S. Government's Official Web PortalDepartment of Health and Human Services
Agency for Toxic Substances and Disease Registry, 4770 Buford Hwy NE, Atlanta, GA 30341
Contact CDC: 800-232-4636 / TTY: 888-232-6348

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