Firefighting water additives improve extinguishing efficiency in both urban and rural settings. The rate and size of forest fires has increased due to anthropogenic factors, making the use of the most efficient fighting tactics extremely relevant. There exists little ecotoxicological data available for many of the products in current use. The aim of this study is to assess the toxicity of firefighting additives currently used in Canada to a variety of aquatic and terrestrial species. Additionally, a deterministic risk assessment was conducted for both aquatic and terrestrial species based off environmentally relevant rates of application. Several of the firefighting water additives tested were found to pose risks to a variety of the species tested, whereas some products appeared to be relatively safe under the worse-case hypothetical scenarios.