Abstract: Background & Aims: Evidence from animal deaths suggested the possible presence of unidentified cylindrospermopsin producers in Central Queensland, Australia. As the water supplies in this region are used by the mining industry for drinking and industrial usage, the ACARP project was designed to identify new toxin producing cyanobacteria that may pose a previously unrecognized human health risk. Methods: A combination of microscopy, chemical analyses, bioassays and molecular techniques was systematically used to identify the cyanobacteria sampled and rapidly assess the presence/absence of genes indicative of known toxins and potential new toxin producers. Results: One hundred and fifty-two strains from thirteen genera were isolated and examined in detail. Of these, eleven strains were recorded as showing toxic effects. One of these strains, Limnothrix, demonstrated novel toxic cellular effects and mammalian toxicity. Various strains with a mix of diacritical morphological characteristics used in the identification of Cylindrospermopsis and Aphanizomenon were isolated. Some of these were also associated with novel toxic effects and belong to the newly created genus Sphaerospermopsis. Conclusions: The diversity of toxin producing species within Australian waters is greater than previously recognized. This research identified a new suite of potentially toxic cyanobacteria for inclusion into health and safety protocols. We are currently investigating the genetics, ecology, toxicity and environmental impacts of these organisms.