These things are poisonous:
Blue-green algae in ponds, bird baths and standing water
Citronella candles
Chlorine
Cleaning products, detergents, bleach and laundry products and their residue
Cocoa mulch
Compost and compost piles, commercial pest control
Fertilizers, indoor and outdoor
Flea products, powders, collars, sprays, drops and shampoos
Many floor products dry or wet
Insect sprays and powders
Lawn fertilizer with weed control
Mothballs
Pine scented products like PineSol
Plant bulbs
Round-up or similar products
Swimming pool and spa supplies
Toxic animals - ants, insects, spiders, toads, lizards, snakes and scorpions and their waste and dead bodies
Turpentine and oil based paint (often licked off fur)
Water from all garden hoses unless clearly marked "made with non-toxic materials"