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Health Canada is advising Canadians to not use malathion products purchased before June 2016

Starting date:
April 27, 2017
Type of communication:
Information Update
Source of recall:
Health Canada
Product Safety
General Public
Identification number:

Health Canada is advising Canadians to stop using pesticides that contain malathion if the product is over a year old. A chemical called isomalathion can naturally form in these products over time, particularly when stored at elevated temperatures. After storage for more than a year, it’s possible that levels of isomalathion could become a concern, even when containers are stored correctly.

Isomalathion may cause symptoms such as nausea, dizziness and irritation to the eyes, nose and throat. As part of a cautionary approach, the Department advises that Canadians who have this product to safely discard it if you are not sure of the date of purchase.

Health Canada is committed to the health and safety of Canadians. Beginning in 2017, new products containing malathion must have labels that have an expiry date.

In the meantime, Canadians should be aware that they may encounter older labels during this current period of transition and that these labels will not display an expiry date. As such, Health Canada advises Canadians not to use products purchased before June 2016.

In Canada, malathion is a registered insecticide used mainly to control insects in agriculture, but it can also be used in and around the home. When used according to label directions, malathion is effective in killing mosquitoes and other pests without posing unacceptable risks to human health or the environment.

What you should do

Examine your product label. If the label does not display an expiry date, and if you purchased the product before June 2016, or if you are unsure of when you purchased it, do not use it.

Make sure any products containing malathion are stored in a cool (around 20-23°C), dry and well-ventilated place, away from seed, fertilizer or other pesticides.


If you need to dispose of any existing products, you should contact your provincial regulatory agency or local municipality for information on how to properly dispose of household hazardous waste in your area. 

Canadians should always read the entire label before using a pesticide and follow all label directions. To check for the most recent product information, visit Health Canada’s web site.

Commercial and agricultural users

As most pesticide products are formulated to be stable over a reasonable amount of time, Health Canada does not object to the use of malathion products that have been purchased before June 2016, provided all of the following criteria with respect to isomalathion are met:

  • The user must conduct a test, using an accredited laboratory, to determine the levels of isomalathion, and the test results for isomalathion must meet the accepted standards (i.e., the World Health Organization specifications) before each use season;
  • The test results are maintained for each use season; and,
  • The product continues to be used in accordance with the other label directions (including storage conditions).

For information on the disposal of unused or unwanted commercial or agricultural pesticides contact the manufacturer or the provincial regulatory agency. To check for the most recent product information, visit Health Canada’s web site or try the new pesticide label search mobile app.

What Health Canada is doing

Health Canada has been working with the manufacturers to ensure that, beginning in 2017, new malathion product labels display an expiry date. In addition, Health Canada will also be monitoring compliance of commercial users who are required to provide acceptable test results for malathion products purchased before June 2016.

Report health and safety concerns

Canadians are encouraged to report any adverse events to the manufacturer, who is required by law to report to Health Canada. You may also report an incident directly to Health Canada by completing an incident report form.

For more information

Media enquiries

Health Canada
(613) 957-2983

Public enquiries

(613) 957-2991
1-866 225-0709