Frequently Asked Questions

(Click on links for answers)

1. What are pesticides?

2. Are pesticides harmful to one’s health?

3. Are pesticides safe?

4. Does the Canadian Cancer Society support a ban on the cosmetic [unnecessary] use of  pesticides?

5. Do herbicides contain dioxins?

6. Aren't there thousands of studies indicating that the herbicide 2,4-D is okay, so what's your concern?

7. What is "bought  science" that I hear so much about?

8. How are pesticides assessed?

9. Why a by-law? Isn't public education enough?

10. Did Québec recently restrict pesticide use?

11. Is Halifax's pesticide bylaw working?

12. How are people exposed to pesticides?

13. If pesticides are used as directed, do they still have a health impact?

14. Isn’t pesticide spraying a private property right?

15. Won’t cutting pesticides reduce property values?

16. Is there support in the community for pesticide reduction?

17. Isn't agricultural pesticide use more prevalent than residential use? Will that come next?

18. Why focus only on landscaping pesticide use?

19. Has anyone died as a result of exposure to pesticides? (long-term exposure?)

20. Are children and pets more vulnerable than others?

21. If pesticides are just used once in a while, can they still be harmful?

22. If I spray pesticides on my lawn, how long should I wait before the grass is safe to sit or play on?

23. Do pesticides harm wildlife?

24. If my neighbour uses pesticides, can it leach into my backyard or blow onto my property?

25. What is the federal government’s position on pesticide use?

26. Can I still have a full green lawn without pesticides?

27. I heard about a lawn care company that applies toxic pesticides while claiming to be ecologically friendly; isn't that misleading  consumers?

28. Do alternatives cost more?

29. Do alternatives take more time to apply and show results?

30. What about people with health conditions such as asthma? Are alternatives  effective?

31. Where can I find information on alternatives?

32. What about the indoor use of pesticides? Isn't that a concern?

33. Q & A from the Pest Management Regulatory Agency (PMRA)

34. Will golf courses be included in the bylaw?


1. What are pesticides?

The term "pesticide" refers to chemical substances that are biologically active and interfere with the  normal biological processes of living organisms deemed to be pests, whether these are noxious plants or weeds, insects, mould or fungi. (Toronto Public Health, April 2002). A “pesticide” is anything used to kill weeds, insects, plant diseases and other unwanted living things. They include herbicides, insecticides, fungicides and rodenticides.  Watch a video on the adverse health effects of pesticides by clicking here.


2. Are pesticides harmful to one’s health?

Pesticides are among the most widely used chemicals in the world, and also among the most dangerous to human health. They are a leading cause of poisonings here in Canada and have been estimated to account for thousands of deaths each year globally. Pesticides can also cause chronic health effects due to both acute poisonings and from chronic long-term exposure. Many studies have documented adverse health effects on humans. Among several areas of concern, many of the commonly used  household insecticides are organophosphates, which have been linked in many studies to neurological  damage in humans. Watch a video on the adverse health effects by clicking here. For further information please visit the Canadian Association of Physicians for the Environment's website at: CAPE and the Ontario College of Family Physicians at: OCFP.  Also click here for our human health page.


3. Are pesticides safe?

Pesticides are registered by the Federal Government, but it is against the law to claim that they are "safe".  Approval only means that pesticides are deemed not to pose "unacceptable" risk  if used under particular circumstances, in particular ways. Many pesticides have never been evaluated with modern methods. Modern testing still does not investigate many mechanisms of toxicity.

Throughout North America, pesticide manufacturers and applicators have been fined and sued for millions of dollars because of illegal  and misleading advertising of safety.

Bill C-45 (Westray), in effect since March 2004, states that employers are responsible for ensuring  workers' safety. Thus if a pesticide makes an employee sick, the employer may be held criminally responsible.

The Krever Commission established that government officials must protect citizens in a timely fashion when evidence (not even absolute) indicates that a product is harmful or has potential to cause harm. Pesticides should not be an exception.

Canada's federal Commissioner of the Environment and Sustainable Development audited in 2003 Canada's pesticide approval process and found major flaws. The Commissioner concluded that: "Canadians want to know: Just how safe are the pesticides we use? The federal government should be able to answer that question. But it can't."

An Ottawa scientist explains why science can't prove a pesticide is safe.


4. Does the Canadian Cancer Society support a ban on the cosmetic [unnecessary] use of pesticides?

Yes, they strongly support such a ban. Their media releases are found here and here.


5. Do herbicides contain dioxins?

Weedkillers 2,4-D,  Mecoprop and Dicamba are three of the top five landscaping chemicals. These three chemicals are  often combined in products such as Killex and Par III. They are known as phenoxy herbicides. By nature of the way they are synthesised, they are inevitably contaminated  with chlorinated dioxins. These persistent, bioaccumulative toxic substances are linked to cancers, and to reproductive, immunological and neurological  problems. There have been allegations of criminal fraud concerning dioxin contamination in products such as 2,4-D (see: Monsanto). For additional information on dioxins, please click here.


6. Aren't there thousands of studies indicating that the herbicide 2,4-D is okay, so what's your concern?

Some of these studies focus on pure 2,4-D, but not the final product that generally ends up being sprayed on lawns. For example, when you see a commercial pesticide applicator spraying herbicides on lawns, that 2,4-D is normally mixed with other herbicides such as  Dicamba and Mecoprop ("phenoxy herbicides"  marketed as Par III or Killex), along with contaminants and formulants (possibly ingredients to make the pesticide spread, stick, join or penetrate better). In our opinion, it is this toxic mixture of chemicals that has not been adequately studied. Synergistic effects are poorly understood.  Mecoprop is eventually being replaced with "mecoprop-p", so it will never be assessed according to today's standards. Nevertheless, it will stay on the shelf until 2009.

A recent study published in the "Toxicology Journal  Environmental Health Perspectives", revealed that the commercial, off-the-shelf mixture of 2,4-D, Dicamba and Mecoprop may pose  serious reproductive risks. Furthermore, 2,4-D and  other phenoxy herbicides are contaminated with  chlorinated dioxins. These persistent, bioaccumulative toxic substances are linked to  cancers, and to reproductive, immunological and  neurological problems. Concern over 2,4-D is such that it is currently not approved for use on lawns and gardens in Québec, Sweden, Norway and Denmark. Accordingly, cancer rates in Sweden dropped once pesticides were restricted. A top 10 list on why you should not use 2,4-D may be read here.


7. What is "bought  science" that I hear so much about?

"Bought science", not to be confused with "junk  science"  or "sound  science"  describes studies whereby unfavourable scientific test results are suppressed in order to support desired outcomes. In other words, "he who pays the piper calls the tune." An example of possible fraud is provided here. Many studies considered for pesticide registration are also "proprietary" and cannot be independently reviewed. Also, many concerned Canadians are critical of bought science  because it has potential to contaminate the pool of accurate and objective peer-reviewed studies. Consequently, many Canadians are urging the Canadian  Government to require the Pest Management Regulatory  Agency (PMRA) to do its own independent pesticide testing rather than relying upon the pesticide industry's science, as is now the case. Click here for our Why Federal Regulations Don’t Work page.


8. How are pesticides assessed?

The Federal Government’s Pesticide Management Regulatory Agency registers pesticides if their studies demonstrate that the probability of a variety of risks is below a defined threshold (the risk is "acceptable") and if the product does what it is advertised to do (kill  the target species). There is no assessment of the need for a product (i.e. do less-toxic alternative products or strategies exist, such as a dandelion-digger?). No risk/benefit assessment is carried out.

 Science may allow assessment of risks; science may be co-opted to obscure risks by posing questions that ignore important contaminants or breakdown products.  However, no science can determine the degree of "acceptability" of risk.

Canadians are now demonstrating that they are not prepared to entertain significant risks to kill weeds, by passing bylaws and, in Québec, the Pesticide Code.


9. Why a by-law? Isn't public education enough?

A study of pesticide reduction initiatives in North America and Europe concluded that public education was important but not sufficient, and that legislation was necessary to achieve non-toxic, sustainable landscaping practices.  The study is entitled: "The Impact of By-Laws and Public Education Programs on Reducing the Cosmetic / Non-Essential, Residential Use of Pesticides: A Best Practices Review".  Click here to download the study.


10. Did Québec recently restrict pesticide use?

In 2003, Québec determined that the risk of pesticides wasn't worth it and announced that products containing 2,4-D and a host of other lawn pesticides are no longer permitted for use in urban areas, as of April 2004. For more  info, click  here.


11. Is Halifax's pesticide bylaw working?

Yes it's working very well. Read more . . .


12. How are people exposed to pesticides?

Pesticides can enter a person’s body by three possible routes: by the lungs, by the mouth or through the skin. Spray applications of pesticides increase the chance that  the applicator and by-standers may inhale fine  droplets. Lawn care pesticide residues may also be  tracked into the home. Children are more likely to be exposed by inadvertent ingestion of pesticide residues on objects in their environment. (Toronto  Public Health - Playing it Safe)


13. If pesticides are used as directed, do they still have a health impact?

Chemical pesticides need to be regulated by the federal government (Pesticide Management Regulatory Agency)  due to their health impacts. Even with approval, the  PMRA acknowledges that there are associated risks  that can be managed through labeling information.  (Toronto Public Health, April 2002) For example, a label might indicate that a product might be considered “safe to use” provided that humans are not exposed.


14. Isn’t pesticide spraying a private property right?

No. Pesticides are known to move from the point of application into air, water  and soil. They don’t stay on the property where they are sprayed. Additives such as solvents, contaminants and break-down products may be more dangerous to the health of neighbours than the pesticide itself. Birds, butterflies and other wildlife don’t stay on a single property. Many pesticides kill them.


15. Won’t cutting pesticides reduce property values?

Not if the reduction is done city-wide so it’s a level playing field. In fact, improving Calgary’s reputation as a healthy place to live will increase the desirability of Calgary homes to those considering moving here, hence property values.


16. Is there support in the community for pesticide reduction?

Yes. 4 out of 5 Calgarians would support phasing out the cosmetic use of lawn pesticides on private property, according to a Feb. 2006 public opinion poll conducted by Oraclepoll Research for CAPE (The Canadian Association of Physicians for the Environment) and the Sierra Club. The poll also revealed that 71 % of Calgary residents believe lawn pesticides pose a threat to children. An even higher percentage of Calgarians said pesticides pose a threat to the environment, including wildlife, air quality and groundwater. Many national polls have found support of over 80% for restricting the cosmetic use of pesticides. Over the last decade the number of municipal pesticide by-laws adopted in Canada has increased to over 125. source When all the current regulations and by-laws come into full effect the total number of Canadians thereby protected from unwanted exposure to synthetic lawn and garden pesticides will grow to over 12.8 million or approximately  40% of Canada's population. (based on the 2001 StatsCan Census).


17. Isn't agricultural pesticide use more prevalent than residential use? Will that come next?

Pesticide application, per hectare, is much more intensive for landscaping than for agriculture. Efforts are focused on the cosmetic [unnecessary] use of pesticides because, by definition, there is no health benefit. Farms are in a crisis and there is no need for the city to tell farmers how to farm. As well, there is no evidence that agriculture is a big problem. Farmers have financial incentives to reduce pesticide use, and are doing so. The City of Ottawa Surface Water Monitoring study found only landscaping pesticides. Pesticides that are restricted, only for agricultural use, were not detected. Pesticides running off lawns and gardens are the problem. Nevertheless, residents in the rural area are very concerned about contamination of their drinking water and environment. As people become used to sustainable gardening at home, they tend to become more interested in locally grown food.


18. Why focus only on landscaping pesticide use?

Pesticides should not be in the environment where children play. Activities on our properties, such as the application of pesticides, have the potential to affect the health of our neighbours and the health of the urban environment.


19. Has anyone died as a result of exposure to pesticides? (long-term exposure?)

The Canadian Association of Physicians for the Environment takes the position that pesticides have been estimated to account for thousands of deaths each year globally. Check out the Canadian Association of Physicians for the Environment's position statement [link to this off the human health - health studies page] and website for more information.


20. Are children and pets more vulnerable than others?

Children are particularly vulnerable due to the specific characteristics of their development and physiology. For example, they eat more food, drink more water and breathe more air per kilogram of body weight than adults and can thus absorb larger quantities of the pollutants present in the environment. (House of Commons - Pesticides Report)

In general, studies find that children have a lower tolerance for pesticides. On the whole, children are typically more sensitive to the effects of pesticides because the  enzymes and organs that rid their body of toxic chemicals are not fully developed. Children are also smaller and lighter than adults, so they receive a  proportionately larger dose per exposure than adults.  (Toronto Public Health, April 2002). Pesticide  exposure during critical times during early development may affect children, or even their children.


21. If pesticides are just used once in a while, can they still be harmful?

There are risks whenever there is human, animal and environmental exposure to chemical pesticides.


22. If I spray pesticides on my lawn, how long should I wait before the grass  is safe to sit or play on?

Warning labels on chemical pesticides give a good indication of the toxicity of the product. However, "safe" is  a very subjective term. Unfortunately, due to both environmental and human variables, there is no certainty that toxic substances will react according to label specifications.


23. Do pesticides harm wildlife?

The scientific research that describes the impact of pesticides on wildlife suggests that pesticides affect reproduction, growth, neurological development, behaviour and the functioning of the immune and endocrine systems. (House of Commons - Pesticides Report)


24. If my neighbour uses pesticides, can it leach into my backyard or blow  onto my property?

Pesticides are known to move from the point of application into air, water and soil. Wind, rainfall and dust carry pesticides to neighbouring properties. In 2003, harmful levels of pesticides were found in Ottawa's  waterways.


25. What is the federal government’s position on pesticide use?

"The Government of Canada is committed to ensuring that Canadians are better protected from health and environmental risks posed by pesticides. “ (Government of Canada web site)

In 2002, Anne McLellan, then Minister of Health, introduced in the House of Commons a bill to enact a new Pest Control Products Act (PCPA). The bill is designed to safeguard Canadians, especially children, and will help ensure a safe and abundant food supply. Pesticides must receive registration from the federal government, under the Pest Control Products Act, in order to be used in Canada. This Act came into force in 2006.


26. Can I still have a full green lawn without pesticides?

The best lawns on the street are often the organically maintained ones.  Chemically-dependent lush, green lawns are prone to disease. Many lawn care companies and garden centres now specialize in organic gardening and non-chemical alternatives and can offer expert advice and service.  There are numerous successful Calgary organic lawn care companies. To find one near you, please click here for a listing.


27. I heard about a lawn  care company that applies toxic pesticides while  claiming to be ecology friendly; isn't that  misleading consumers?

The Competition Bureau has found that statements such as "ecology  friendly" can be misleading consumers. As a result, the Competition Bureau released a public warning to consumers. If you witness a lawn care company claiming to be ecologically friendly while they spray noxious pesticides, then please notify the Competition  Bureau.  Additionally, in 2003, false / misleading advertising  was found by the PMRA to have occurred from pesticide manufacturers: Bayer, Syngenta as well as the following lawn care companies: Weed Man, and Bobby Lawn Care (source).


28. Do alternatives cost more?

Commercially applied alternative treatments generally cost between 10 and  25 % more. Otherwise, it can arguably be a less expensive proposition if the only investment you need make in your lawn is a little extra personal attention. Once established, organic lawns are more resilient and less expensive to maintain than lawns on soil that has been depleted of organisms by chemical applications.


29. Do alternatives take  more time to apply and show results?

Yes, unlike chemical treatments that are designed to kill problems instantly, alternative measures may take time to cure a chemical-dependent lawn. However, the results will last.


30. What about people with health conditions such as asthma? Are alternatives effective?

Pesticides have been reported to aggravate asthma symptoms and in some cases may induce asthma  (references: here and here [link to Brazil pesticide poisoning article off human health studies page - on our site - a pdf called asthma]).  Non-chemical alternatives are considerably safer to humans than chemical pesticides. If alternatives are not able to provide a healthy environment, the use of low-toxicity chemicals needs to be considered to control noxious weeds.


31. Where can I find information on alternatives?

To get information on  alternatives to chemical pesticides, residents can check out our lawn and garden tips.


32. What about the indoor use of pesticides? Isn't that a concern?

The indoor use of toxic pesticides can pose serious health risks. An increased risk of leukemia has been associated with indoor pesticide use. Additionally, Ontario Provincial Court documents reveal that  Ottawa-Gatineau Germex Exterminators broke laws while applying and storing pesticides. Why take the risk? The Coalition for a Healthy Calgary supports only safe organic approaches to indoor pest  control.


33. Q & A from the Pest Management Regulatory Agency (PMRA):

Q: How many  licensed Canadian Medical Doctors are employed by the  PMRA?

PMRA Answer:  None (as of May 2006)

Q: Is it  correct to say that pesticide use is 'safe'? If so,  in which part of the Pest Control Products Act  governing pesticides would this indication be found?

PMRA Answer:  It is not appropriate or legal to say a control  product (pesticide) is 'safe'.

Q: Does Pest  Management Regulatory Agency (PMRA) documentation  exist that would allow a licensed applicator to make the claim that registered pesticides are 'safe'?

PMRA Answer:  No provision exists to allow a licensed applicator to  claim a control product is 'safe'.

Q: Are pesticides approved for usage because they are proven  'safe'? If not, on what basis are they approved?

PMRA Answer:  The PMRA conducts assessments on the risks and value of the control product specific to its proposed use.  Only text from the approved control product label can be used to describe/advertise that product.

Q: Does the  PMRA evaluate the breakdown products of formulants that are contained in pesticides?

PMRA Answer: The PMRA does not necessarily know or evaluate the breakdown products for a specific  formulant (molecule) on its own. The breakdown products would most likely vary depending on how it  is used, what other chemicals are used in conjunction  with a specific formulant.  However, the  transformation products are examined during the registration of a product for the entire formulation  (the active ingredient and formulant together).


The following FAQ’s are written by the Coalition for a Healthy Calgary


34. Will golf courses be included in the bylaw?

Ideally, we would like them to be included in the phase out of unnecessary pesticide use. Golf courses are generally heavy users of pesticides when they use them. There are also success stories of golf courses going organic, such as the Banff Springs golf course and the prestigious Granite Club golf course in Toronto, A middle way could be to adopt the measure in the Peterborough bylaw, that pesticides can only be applied by a groundskeeper certified in Integrated Pest Management (IPM) to the standards of the Audobon Cooperative Sanctuary System of Canada.