This information is part of a packet of information that was put together to counter an attempt by some people to prevent the Pennsylvania Department of Transportation from using herbicides in their roadside vegetation management programs.  It applies just as well to the use of herbicides in landscapes.

You don’t know what you’ve got ‘til it’s gone

Before pesticides were developed to the point that they could be used extensively, man’s struggle with the environment was extremely time-consuming and often unproductive.  The need for help was perceived to be so great that the person who developed DDT, Paul Muller of Ciba-Geigy, received the Nobel Prize in medicine for its discovery.

The Pennsylvania Department of Transportation (PDOT) has safely used herbicides as a part of its vegetation management program for many years.  There are several reasons herbicides are used.  Controlling vegetation with herbicides is safer, faster, and less costly than with physical methods such as cutting or mowing.  Herbicides can do things that physical methods cannot.  Selected herbicides can move into the roots of perennial weeds to kill the entire plant and limit re-growth following treatment.  They can provide season-long control of vegetation in certain areas with only one application per year.

Despite the benefits provided by herbicides as part of a vegetation management program, their use is being challenged by some citizens groups, and in response, some parts of the political system.  The purpose of this section is to allay the fears of those opposed to the use of herbicides by  the PDOT.

Despite the fact that some people feel that all pesticides are highly toxic and dangerous to humans and their environment, there is no evidence supporting this belief, and much evidence refuting it.  Like many other chemical products, herbicides can be harmful, but they are applied sparingly to specific targets in controlled manners, by experienced workers and in compliance with government-approved specifications.  Key articles referenced below provide convincing evidence that the herbicides used by PDOT are safe for use along roadsides and pose no threat to the highway user or adjacent property owners.

How poisonous are herbicides?

The “2004 Annual Report of the American Association of Poison Control Centers Toxic Exposure Surveillance System;” compiled by William Watson PharmD, Toby Litovitz MD, George Rogers, Jr. MD, Wendy Klein-Schwartz PharmD, Nicole Reid Med, Jessica Youniss MBA, Anne Flanagan MS, Kathleen Wruk MHS; includes 2,438,644 human exposure cases reported by 62 participating poison centers during 2004.  Of all reported cases 92.7% occurred at a residence, with only 2% occurring in a workplace.

Of 1,183 human fatalities reported, 919 were intentional (suicide, misuse, abuse, etc).  Three were attributed to herbicides, but all three involved suicides.  An additional 5 were attributed to insecticides or other pesticides, and again all involved suicides.

Table 1.  The following list of material categories and the numbers of fatalities associated with each is presented for comparative purposes (2004):

Anti-depressants                                                                      299
Analgesics                                                                                 658
   (aspirin, acetomenaphin, ibuprofen, opiods)
Stimulants and Street Drugs                                                  214
Antihistamines                                                                          55
Cosmetics/Personal Care                                                      3
Vitamin Supplements                                                              3
Herbicides                                                                                 3 (all suicides)
All Other Pesticides                                                                  5 (all suicides)

Table 2.  A summary of the total number of people reported to be exposed to selected materials, and the outcome of those exposures. The numbers listed do not represent the total exposed because the medical outcome data were also collected in categories labeled “unknown, non-toxic, “unknown, potentially toxic”, and “unrelated effect” (2004).

Material/ total exposed                       None         Minor         Moderate         Major      Death

Herbicides                                              1,940        2,285               335                 14             3

Analgesics                                            66,114      43,547            24,393           5,685        658
(aspirin, etc; opiods)

Cleaning Substances                        43,056      52,502             8,222              328           24

Cosmetics/Personal Care
Products                                               42,155      27,310             2,485              106             3

Plants                                                    14,982       6,278              1,442               80              5

Vitamin Supplements                        14,199       3,453                566                 53             3

Mushrooms                                           3,769       1,094                848                 59             5

Are herbicides a threat to cause cancer?

Drs. Brian E. Henderson, Ronald K. Ross, and Malcolm C. Pike of the Department of Preventive Medicine and the Kenneth Norris, Jr., Comprehensive Cancer Center in the University of Southern California School of Medicine wrote a review article for Science (Vol. 254:1131-1138. 1991) magazine titled, “Toward the Primary Prevention of Cancer.” Based on an extensive review of the literature relating to cancer and its causes, they concluded: “We now have sufficient knowledge to move energetically toward the prevention of a significant proportion of human cancer. The majority of the causes of cancer (such as tobacco, alcohol, animal fat, obesity, ultraviolet light) are associated with lifestyle; that is, with personal choices and not with the environment in general. The widespread public perception that environmental pollution is a major cancer hazard is incorrect.”

In addition, “The American Academy of Family Physicians” adopted the following resolution in 1992:
         “Whereas, alleged risks of the American food supply produced with agricultural chemicals have aroused concerns in patients, including expectant mothers, parents of small children, the elderly, and those with chronic diseases; and
         Whereas, the quality, variety, and quantity of the American food supply have been documented as the major factors in the decline of stomach cancer rates over the past 50 years and are the envy of the world; and
         Whereas, the public and the media need guidance of medical professionals in assessing health claims for benefits or hazards of the American diet; therefore,
         Be it resolved, The American Academy of Family Physicians:  Acknowledges the improving quality of the American food supply and the major contributions of American agriculture to our patients; this acknowledgement to be communicated to the consuming public through the media and to farm organizations, And will continue to follow the most prudent guidelines to protect our patients and promote optimal nutrition."

Are herbicides a threat to the environment?

In 1983 W.C. Bramble and W.R. Byrnes published “Thirty Years of Research on Development of Plant Cover on and Electric Transmission Right-of-Way” in the Journal of Arboriculture Vol. 9(3).  A study of vegetation development and production of wildlife food and cover was made on an electric transmission right-of-way (ROW ) in central Pennsylvania over a period of 30 years.  Vegetation was maintained with herbicide sprays compared with hand-cutting on separate areas assigned in a randomized block design over a 3-mile segment of ROW.A low plant cover resistant to tree invasion was developed which changed from dominant forest plants (bracken, vernal sedge, loosestrife, witch-hazel, and blueberry) to a relatively stable proclimax maintained by spraying and which was dominated by a combination of forest plants plus plant of openings (sweetfern, blackberry, dewberry, goldenrods, and hayscented fern). All of these dominant plants spread vegetatively by rhizomes or shallow roots to produce a mosaic pattern of irregular patches. Wildlife food and cover was increased on all areas and valuable shrubbery edges developed. This produced a high wildlife habitat rating for the ROW as compared with the adjoining forest.

In their article “Effects of Special Right-of-Way Maintenance on an Avian Population” (Journal of Arboriculture (12(9):219-226. 1986), W.C. Bramble, W.R. Byrnes, and M.D. Schuler reported the results of a study on the effects of five right-of-way (ROW) maintenance techniques on birds living in an electric transmission line ROW in central Pennsylvania. The techniques included hand-cutting, and four different herbicide applications. An important feature of these techniques was a differential treatment of wire and border zones of the ROW. Bird censuses made before and after treatment indicated that the total number of birds of the six most common species were not significantly affected by any of the treatments.

If herbicides are safe, why are some people concerned?

In 1985 Dr. Neil Orloff, Director of the Center for Environmental Research, Cornel University, Ithaca, New York, presented three reasons Americans are afraid of chemicals in the magazine Agrichemical Age, March, 1985.  The following excerpts are from the Wall Street Journal report on the article.

  1. The focus on pollutants provides a simple and plausible explanation for dreaded diseases such as cancer and birth defects. It provides a ready answer, other than pure chance, for their occurrence. Moreover, this explanation exonerates the victims from responsibility for their personal lifestyle decisions contributing to the outcome, such as the foods they eat, the amount of alcohol they drink, and the extent to which they smoke.  Instead of blaming themselves and their own actions, people can thus contract the causes for disease into a “single, unavoidable event”.
  2. Focusing on the risks of pollutants helps maintain people’s image of the sanctity of nature. Many are discomfited by the discovery of thousands of toxins naturally present in the air and water, because it conflicts with their notion of a pristine environment. The ubiquity of toxic substances demands either a new, less benign conception of nature, or an all-out attach against the ‘unnatural’ risks posed by these substance in the environment.
  3. Anxiety about pollutants provides an outlet for the anti-business feeling in the United States, particularly our society’s strong resentment of the power and perceived indifference of large corporations.


From: "WSSA"
To: Larry J. Kuhns
Subject: WSSA: EPA Public Comment on 2, 4-D Registrations
Date: Thu, 15 Jan 2009 17:30:53 -0600

WSSA Members:

In the December 24 Federal Register, EPA requested public comment on a petition from the Natural Resources Defense Council (NRDC) to revoke all tolerances and cancel all pesticide registrations for the herbicide 2,4-D. As you are aware, this herbicide is used on a variety of crop, turfgrass, aquatic, and noncrop situations across the country and thus it is an important tool for broadleaf weed control.

The petitioner, NRDC, claims that EPA cannot make a finding that there is a reasonable certainty of no harm from dietary residues of 2,4-D and, therefore, that the Agency must revoke all tolerances established under section 408 of FFDCA, as amended by FQPA.

As a part of the petition, NRDC claims that the Agency did not consider the full spectrum of potential human health effects associated with 2,4-D in connection with EPA's reassessment of the existing 2,4-D tolerances, and EPA's environmental risk assessment including:

1. Information on the endocrine disrupting effects of 2,4-D.
2. Information on the neurotoxicity related to 2,4-D exposure.
3. Information that products containing 2,4-D are mutagenic.
4. Data showing that dermal absorption of 2,4-D is enhanced by alcohol consumption, sunscreen, and DEET which the EPA's exposure assessment failed to include.
5. Information about adverse developmental effects at doses below those included in EPA's risk assessment for exposure of infants to 2,4- D in breast milk.

Source: Federal Register: December 24, 2008 (Volume 73, Number 248)

Web site: The Federal Register notice is at

The NRDC petition is in Docket ID No. EPA-HQ-OPP-2008-0877, available at

Risk assessment and related documents for this pesticide can be found under docket ID number EPA-HQ-OPP-2004-0167, available at

We encourage you to submit your comments directly to the EPA on this proposed action.     Comments may be submitted via to docket EPA-HQ-OPP-2008-0877 and are due on or before February 23, 2009.  Use this website:

The WSSA and affiliated societies plan to submit comments to the EPA on this proposed cancellation.  Lee Van Wychen and the Science Policy Committee will be developing the response from WSSA.  If you would like to help us in this effort, please let Lee  ( or me know as soon as possible.

Thank you for your assistance.

Jeffrey Derr
WSSA President