The Canadian government published a final pesticide re-evaluation decision July 22 for boric acid, with Health Canada's Pest Management Regulatory Agency, under the authority of the Pesticides Act, granting continued registration for most uses in Canada. It is a naturally occurring substance that is commonly used in a wide range of pesticides in Canada to control insects and fungi. The re-evaluation includes the active ingredients boric acid, borax (pentahydrate), borax (disodium tetraborate decahydrate), disodium octaborate tetrahydrate and zinc borate, the non-antisapstain uses of which, registered in Canada, include the control of a broad range of insects and fungi in structures, wood, and wood products. Zinc borate (a salt of boric acid) is registered for use as a wood composite preservative and as a material preservative in the manufacture of paints, coatings, plastics, and rubber.
There are a total of 110 pesticide products registered for use in Canada containing boric acid, and 25 of those will have their registrations cancelled while the remaining 85 will have to meet new labeling requirements within the next two years. "Even natural ingredients like boric acid can pose a risk to Canadians. That's why Health Canada looks at all pesticide ingredients to make sure we are not being exposed to levels that could be a concern. These steps, including cancelling some registrations and introducing new, more stringent label requirements for others, are science-based interventions that will help protect Canadians," said Minister of Health Jane Philpott.
The agency evaluated available scientific information and found that most of these uses of boron do not pose unacceptable risks to human health or the environment when used according to the revised label directions. As a requirement for the continued registration of these uses, label amendments are required for all end-use products, however, and certain uses are to be cancelled to address risks of concern to human health. These uses are:
• Commercial dust/soluble powder formulations applied to poultry houses and barns
• Commercial solution/soluble powder formulations applied by paintbrush
• Domestic dust and granular formulation products, as well as solutions that are not in enclosed bait stations.
Alternatives are readily available for the affected products and uses, according to Health Canada.
The cancelled registrations means those pesticide products containing boric acid for use in and around the home will be phased out of the marketplace. These are products in powder form or other formats where there is a potential risk of overexposure for Canadians.
The government is also conducting a broader review of boric acid under the Chemicals Management Plan and has published a draft risk assessment for input from Canadians. Based on the draft risk assessment, Health Canada is advising Canadians to avoid using boric acid for arts and crafts projects or in homemade pesticide mixtures.
Registered pesticides regularly undergo re-evaluation to ensure that they continue to meet modern standards for human health and environmental protection.