When my dogs were alive, I avoided using herbicides in my yard. While chemical labels state safe reentry times after application, I just never felt comfortable about it. Recently an article came across my desk about herbicides being detected in the urine of pet dogs following home lawn herbicide application. This has been associated with “significantly higher bladder cancer risk in dogs” (http://weedsnetwork.com/traction/permalink/WeedsNews4419).
The chemicals tested were some of the common ones used for lawn weeds: 2,4-D, MCPP and dicamba. Not only are these chemicals found singly in herbicide products, they are often found in fertilizer/weed killer combination products.
What I also found interesting in this study is that chemicals were found in dog urine prior to lawn treatment with herbicides, after lawn treatment and in dogs on untreated lawns. This suggested that dogs were picking up chemicals that blew into their yards and from visiting other areas that had been treated.
Dogs are at risk because they get chemical residues on their fur and paws, which they lick. They may inhale chemicals as they roll or play on the grass. While you may not use herbicides on your lawn, they are often used in parks or other places you might take your dog.
As I looked further into studies and then into the US Environmental Protection Agency response to these studies, I realized that the studies were inconclusive about the dangers to dogs of exposure to lawn chemicals. In 2012 the EPA stated that while additional research on connecting 2,4-D exposure to cancer in dogs was warranted, “it does not believe that there is evidence of critical animal health issues which warrant changes to its current conclusions” (http://www.epa.gov/pesticides/chem_search/reg_actions/24d/24d-issue-response.pdf). What this EPA response didn’t take into consideration was other kinds of active ingredients, or how various ingredients might affect dogs in combination.
Depending on your research bent, you can find articles on both sides of the issue. Some will say pesticides are horrible and cause cancer and others will say they are completely safe. It is up to you to make decisions about your chemical use in your yard and landscape. If you decide using pesticides is acceptable, read and follow the label carefully and exactly. You will find safety information including how long to restrict access to pets and people after using the pesticide, where and how to use the chemical, and safe storage and disposal information. It is your legal responsibility to follow all the information on the label.