The Facts About Diazinon

Why is diazinon dangerous?

December 5, 2000

The Facts About Diazinon: Fact Sheet

This fact sheet presents data culled from EPA’s draft risk assessment for diazinon. The risk estimates will change as the manufacturer submits new studies; however, it is highly unlikely that the EPA will find the risks from these uses acceptable.

Primary Manufacturer

Syngenta (formerly Novartis, a Swiss Pesticide and Pharmaceutical firm)
With production in Macintosh, AL

Other Manufacturers


First Marketed

1948 (according to EPA Pesticide Products Information System)

Pounds Used Per Year

6 million pounds (tied with Dursban for home and garden use)

Primary Usage

  • Outdoor application by homeowners (39%)
  • Lawn care operators (19%)
  • Exterminators (11%)
  • Flea & Tick Collars

Consumer Product Names

Spectracide, Real-Kill, Ortho, Cutter, Peters, Hot Shots, No-Pest, K-Rid and others

Largest Food Uses

  • Almonds (170,000 lbs.)
  • Prunes (66,000 lbs.)
  • Peaches (61,000 lbs.)
  • Pecans (85,000 lbs.)
  • Plums (64,000 lbs.)
  • Sweet Corn, Fresh (48,000 lbs.)

Closely followed by Head Lettuce, Stone Fruits and Berries


Indoor Use is Deemed Unsafe for Small Children


Novartis (now Syngenta) announced on July 24, 2000 that it would no longer support diazinon’s indoor uses including greenhouse application. The company cites lack of funds for the required testing, but EWG suspects that Novartis has given up hope in light of the EPA assessment.

EPA's Risk Assessment shows that children are exposed to diazinon at up to 400 times the EPA's safe dose 24 hours after professional treatment in cracks and crevices.

Exposure Route


(times EPA's 'safe' dose)


(times EPA's 'safe' dose)

Inhalation Exposure 24 Hours After Treatment



Dermal Exposure 24 Hours After Treatment



(*) EPA provided a number of different dermal scenarios. This represents the lowest risk.

Source: USEPA Preliminary Occupational and Residential Risk Assessment for Diazinon (PORRAD)


Diazinon can Pollute Surface and Ground Water


Diazinon is the most frequently detected insecticide in US Geologic Survey’s National Ambient Water Quality Assessment (NAWQA) program. It is found in 24 states plus the District of Columbia, including every major river basin. Diazinon has been found in drinking water wells at levels exceeding EPA’s ‘safe’ level. Diazinon could contribute to unsafe drinking water exposures for children.


Diazinon Poses a Risk to Pacific Salmon


Runoff of diazinon has reached unsafe levels in Northwest watersheds creating a threat to salmon populations. Diazinon interferes with juvenile Chinook salmon’s ability to detect alarm chemicals in the water leaving them vulnerable to predator attacks. Since diazinon is a broad spectrum insecticide, it also impacts the insects and other animals on which the young salmon feed. The dose of diazinon inhibits reproductive behaviors and may also cause genetic damage in fish. The EPA has come under a lawsuit for failing to develop a plan to safeguard salmon from pesticides under the Endangered Species Act.

Source: Cox, C., 2000, Lethal Lawns: Diazinon Use Threatens Salmon Survival, J. Pesticide Reform.


ALL Uses are Currently Deemed Unsafe for the Home Applicator


Application Method

Exceeds EPA’s ‘Safe’ Dose by a factor of

Lawn Granules Applied with Push Spreader


Lawn Granules Applied with ‘Belly Grinder’


Lawn Application with Garden Hose Sprayer


Typical Garden Application with Spray Wand


Typical Garden Application with Paint Brush


Note: Table does not list all uses. Estimates include both dermal and inhalation risk



Diazinon Victims


Source: EPA Review of Diazinon Incident Reports, 1998

Two female gardeners in Singapore knocked over a container of diazinon. After cleaning up the spill, one of the women experienced diarrhea, dizziness, frothing at the mouth, and pulmonary edema requiring a respirator. She later developed acute pancreatitis.

An 18 month old boy in Michigan was accidentally fed "roach milk" (5% diazinon). The boy was taken to the hospital in a coma. He recovered with treatment. (Detroit News, November 29, 1985)

A six-year-old girl had her hair washed for head lice with diazinon. She was hospitalized after full cardiac and respiratory arrest.

Diazinon has been cited in more than 200 lawsuits involving acute poisonings, chronic conditions and at least one death.


Symptoms of Exposure to Diazinon


Exposure to diazinon can result in headaches, diarrhea, or comas depending on the level of exposure. Below is a list of common signs and symptoms of exposure.

Common early or mild signs/symptoms

Present in the moderate or severe poisoning

Presence signifying life-threatening severity

Muscle weakness

Tightness in chest
Difficult breathing
Abdominal pain
Memory loss
Poor concentration
Heavy salivation
Profuse sweating
Blurred vision
Pinpoint pupils

Respiratory arrest
Pulmonary edema
Loss of reflexes
Flaccid paralysis

Source: Review of Diazinon Incident Reports, USEPA Memo, July 1998


Regulatory History



Product first marketed in the US.


Product reviewed by the EPA under the "Special Review" process. Golf course and sod farm uses were cancelled due to high risk for birds feeding on these properties. Home lawn use, however, is maintained. The decision also prohibited application on food crops grown in greenhouses. (51 FR 35034 amended in 52 FR 5656)


Registrant-requested hearing confirmed 1986 decision.


Decision finalized to cancel all use on golf courses and sod farms.


Diazinon has come under FQPA review, which will assess impact on humans, not just birds.