c) Improper storage of poisonous substances.
In one study, improper storage was a factor in 51% of poisonings. Improper monitoring of the child and distraction were factors in 23% and 13%, respectively.
Source: Brayden, R.M., MacLean, W.E., Bonfiglio, J.F., & Altemeir, W. (1993) Behavioral antecedents of pediatric poisonings. Clinical Pediatrics 32, 30-5