Naled General Fact Sheet (2024)

• What is naled?
• What are some products that contain naled?
• How does naled work?
• How might I be exposed to naled ?
• What are some signs and symptoms from a brief exposure to naled?
• What happens to naled when it enters the body?
• Is naled likely to contribute to the development of cancer?
• Has anyone studied non-cancer effects from long-term exposure to naled?
• Are children more sensitive to naled than adults?
• What happens to naled in the environment?
• Can naled affect birds, fish, and other wildlife?

What is naled?

Naled is in a family of insecticides called organophosphates. Productsthat contain naled are used outdoors in some agricultural and residentiallocations. It is only used by trained professionals.

Naled is used to control public health pests like mosquitoes and biting flies,as well as crop-damaging insects.¹ It is one of the most commonly usedpesticides for aerial mosquito control.² Naled was first registered for use inthe United States in 1959.³

What are some products that contain naled?

All products containing naled are liquid. They may be diluted from soluble or emulsifiable concentrates. Currently,there are six products that are registered for use in the United States. All of these products are known as RestrictedUse Pesticides (RUP) and require a license to purchase or apply the product. Naled can be applied aerially in urban orrural areas, in greenhouses, and on some crops.¹ There are no approved uses for naled indoors or on pets.¹

If you are a trained professional that uses naled, always follow label instructions and take steps to avoid exposure. If any exposures occur, be sure to follow the FirstAid instructions on the product label carefully. For additional treatment advice, contact the Poison Control Center at800-222-1222. If you wish to discuss a pesticide problem, please call 800-858-7378.

How does naled work?

Naled quickly affects insects when they touch, eat, or breathe it.⁴ Naled is a cholinesterase inhibitor, which causesthe insect's nerves to continuously 'fire'.³ Usually this firing is stopped chemically inside the insect, but a breakdownproduct of naled prevents enzymes in the insect from working correctly. The insect's nerves are then stimulatedconstantly, and eventually the insect dies.

How might I be exposed to naled?

Naled can be used on some crops to control insects.³ Should you eat food that was treated, you could be exposed tolow levels of naled or its breakdown products in the plant. The U.S. Environmental Protection Agency (EPA) sets legallimits for pesticides on food. These limits help ensure food safety.

For mosquito and public health pest control, naled is used aerially orsprayed from trucks. To protect public health, the EPA limits the amountthat can be applied. These applications are called "Ultra Low Volume(ULV)", meaning a small amount is used over a large area. This limit iscurrently about 2 to 4 tablespoons of formulated product per acre,which is no more than 0.1 pounds of naled per acre.³ That's about thesame as using 1-2 ounces in an area about the size of a football field.

Using naled pesticide products properly and legally requires a license and expertise. Although not required, thefollowing steps may reduce your risk. You may choose to:

• Stay inside during the active application.
• Think about what items have been left outside. Cover or move toys, pet items, bird feeders and baths, playstructures, and grills.
• Close doors and windows of your home when possible. Close car or other vehicle windows left open.
• If your air system pulls in outside air, turn off your heater or air conditioner to prevent naled from being movedindoors.
• Cover edible plants beforehand or wash fruits and vegetables after the application.

If you are outside during or very soon after the application, you could contact very small amounts of the product onyour skin, breathe it in, or get it in your eyes. Contact is unlikely, but wearing long clothing could limit exposure to thechemical. Pets and people could also be exposed to small amounts of naled if they eat or touch grass that was veryrecently sprayed. If direct contact happens, go inside to wash your skin and eyes and call Poison Control at 800-222-1222.

What are some signs and symptoms from a brief exposure to naled?

Naled is moderately toxic if eaten, gets on the skin, or breathed in. In addition, naled is severely irritating if a persongets it in their eyes or on skin.³ It is considered corrosive and direct contact could lead to permanent damage.^3,5

After rats breathed low doses of naled for four hours, they experienced diarrhea. Another group of rats breathingmoderate doses of naled experienced decreased activity, body tremors, diarrhea, and difficulty walking.⁶ Similar toother organophosphates, overexposure from direct inhalation could lead to tightness in the chest, wheezing, cough,increased saliva, runny nose, blurred vision, tearing, and headache.⁷

After spills or other direct skin exposures, symptoms may include itching, redness, rash, and irritation.⁶

Rats fed low doses of naled experienced diarrhea, tremors, salivation, increased urination, and decreased activity.⁶Symptoms reported after human exposures to organophosphates like naled included headache, nausea, dizziness,and sweating, as well as increased saliva, tearing, and runny nose.⁸ If a person has a large exposure, severe naledpoisonings could include feeling lightheaded, slurred speech, muscle twitching, irregular heartbeat, convulsions,paralysis, coma, and death.⁹

Children may exhibit different common symptoms to organophosphates that adults. Muscle weakness, salivation,constricted pupils, seizures, lethargy, and coma were found more often in children than adults.⁸

What happens to naled when it enters the body?

Through all routes of exposure, naled may be absorbed into the bloodstream. Naled is then broken down in theliver.¹⁰ It is excreted from the body in urine, exhaled air, and feces. A feeding study with rats found that 70 to 80percent of the dose was excreted within 48 hours.⁶ Naled and its breakdown products are not expected to build upin human or animal bodies.³

Several groups of rats had naled applied to their skin for various times, from 30 minutes to 24 hours. About 21 to 23percent of the original dose was absorbed through the skin.³ Scientists have recommended that a rate of 35 percentbe used to estimate human skin absorption.¹¹

Following exposure in rats, naled was distributed to the gut, liver, and blood at higher concentrations than othertissue. In chickens, naled moved to the kidneys more than other areas of the body. In the same study, naled was alsofound in eggs at lower amounts.⁵

Chickens and goats treated with naled have shown detectable levels of breakdown products in eggs and milk.⁵Holstein cows sprayed with naled for 14 days did not have detectable residues in their milk.⁷

Is naled likely to contribute to the development of cancer?

The EPA has classified naled as demonstrating "evidence of noncarcinogenicity".³ Mice fed naled for 89 weeks did notdevelop tumors at a higher rate than untreated animals. Male rats that were fed naled for two years showed a slightincrease in mammary cancers, but not enough to be considered significantly different from non-dosed rats.⁵

Dichlorvos (or DDVP) is a metabolite of naled, and has been classified as a possible carcinogen by the InternationalAgency for Research on Cancer.¹² The EPA has determined that there is "suggestive evidence of carcinogenicity, butnot sufficient to assess human carcinogenic potential" for DDVP.^13,14 Rats fed DDVP over a two-year study had anincreased risk of cancer in the pancreas and leukemia (a form of blood cancer). Female mice in the same study alsohad a higher risk of stomach cancer. In another study, rats that inhaled DDVP for two years were not found to have anincreased risk of cancer. No evidence of an increased cancer risk from DDVP has been found in people.^12,15,16

Has anyone studied non-cancer effects from long-term exposure to naled?

In two studies, young rats and rabbits did not show adverse effects after their mothers were fed naled duringpregnancy. Naled has been found in human umbilical cords after birth, but it has not been shown to affect humangenes.^6,17 The EPA has not yet tested naled for its potential to disrupt endocrine function.³

Inhalation of naled by rats for 13 weeks found that a high dose caused tremors, salivation, nasal discharge, andabnormal breathing. Increased food consumption, changes in blood chemistry, and increased liver weights were alsofound. Rats fed a medium dose of naled for 28 days found reduced weight gain, increased liver and adrenal weights,skin irritation, and blood and nerve cell inhibition in the brain. Changes in blood were found in rats exposed to naledon the skin for 21 days. Male rats were also found to have increased liver and testicl* weights from a high dose.^3,5

If aerial applications are performed correctly, asthma and asthma attacks are not expected to occur.¹⁸

Because naled is non-persistent, the risk from exposure in food and drinking water does not exceed EPA's level ofconcern. Due to this, exposure to naled is not of concern for people other than naled mixers, loaders, and applicators.

Are children more sensitive to naled than adults?

In general, children may be especially sensitive to pesticides compared to adults. Scientific data indicate that childrenare not more sensitive to naled than adults.^2,3

Young children may also act in ways that put them at greater risk of being exposed. For example, they may spendmore time near the ground. They may also be more likely to place their hands in their mouths after touching treatedsurfaces. If naled is being applied in your area, here are some ideas to help you minimize the risk to yourself andothers.

What happens to naled in the environment?

Naled is non-persistent, and is broken down by soil microorganisms, water,and by light, indirectly.³ It also binds weakly to soil and is moderatelymobile in soil. Both naled and DDVP have been found to be less mobilein soil that is clay-rich, and more mobile in sandy soil. Naled in soil rapidlydegrades, with half-lives ranging from about 30 minutes to 1.4 hours insandy loam soil.^5,19 On inert surfaces exposed to direct sunlight, Naled hasa half-life of about 1-2 hours.²⁰

In water, naled dissolves very poorly.⁷ The half-life of naled in water is dependent upon pH (acidity), with ranges of96 hours (pH 5, more acidic) to 15.4 hours (pH 7) to 1.6 hours (pH 9, less acidic). No groundwater studies have beenevaluated to determine the potential for naled to pose a risk to groundwater.¹⁹ However, estimated concentrations ofnaled in groundwater do not exceed EPA's level of concern for short or long-term exposures.³

Naled can be taken up by plants after application and quickly broken down.⁴ In one study, lettuce, wheat, and carrotswere grown in soil treated with naled. The concentration of residues found in the vegetables did not indicate buildupover time. Following an application of naled onto grounded apples, cabbage, tomatoes, cantaloupe, grapes, andalfalfa, less than 50 percent of naled was found one hour after treatment.⁵

On the surface of grape leaves, naled residue was found up to five days after application. After three days, severalsamples had undetectable levels.²¹ Naled applied to cotton and cucumber leaves was not found in other parts of theplant 1 to 7 days after application.⁵ When applied to crops, it is not expected to be persistent enough for residues topose a risk in later plantings.

Naled tends to rapidly diffuse into the atmosphere prior to degradation. When exposed to natural sunlight, calculatedhalf-lives of naled ranged from 57.8 to 60.7 hours in air, and 99 hours in dark conditions.¹⁰ Naled evaporates quicklyafter application.¹⁹

When naled was applied in fish tanks, DDVP was found to temporarily accumulate in fish tissue within an hour ofapplication. After seven days of exposure, extremely small amounts of DDVP were found in the fish. This indicates thatnaled is not expected to build up in their bodies.^19,22

Can naled affect birds, fish, or other wildlife?

The toxicity of naled is highly dependent upon the type of organism affected. Ingestion and skin exposure of naled ismoderately toxic to mammals such as rats and mice.¹⁰ Naled is moderately to highly toxic when eaten by birds such asmallards, Canada geese, and sharp-tailed grouse. Mallards also showed a reduction in egg production, egg survival,and hatchling survival following long-term repeated exposures to naled.³

Naled is also highly toxic to bees through direct contact (LD₅₀ of 0.48micrograms/bee). Indirect contact with plants was found to be highlytoxic one hour after application and practically non-toxic one day afterapplication.³ During a field application, naled was low to moderate intoxicity to honeybees after three hours.

It is moderately to very highly toxic to freshwater fish and is very highlytoxic to freshwater invertebrates like water fleas, stoneflies, and scuds.Naled is moderately toxic to saltwater fish and highly to very highly toxicto saltwater invertebrates like shrimp, oysters, and mysid shrimp.³

Although long term exposure to naled is unlikely due to its short half-life, repeated exposure for wildlife could occurin the right environment. Naled used regularly on crops such as almonds, citrus, cole, and seed alfalfa has been foundto exceed EPA's level of concern for birds. Crops such as citrus, grapes, and seed alfalfa are high-exposure sites formammals, and potentially exceed EPA's level of concern for chronic exposure to naled. Mosquito applications exceedthe acute exposure level of concern for mammals.³