Something that is toxic can harm or kill. Something that is only mildly toxic may only be an irritant, while something that is strongly toxic could kill rapidly or slowly, depending on the kind of toxin.
A "toxin" is something that is toxic. "Toxicity" is a measure of how toxic or poisonous something is. A substance that is toxic to one resident in a home, may not have the same effect on another. For example, chocolate can kill a dog, but most people (except those allergic to it) can safely eat chocolate.
Many household cleaners, some maintenance materials (like paint or varnish), and some hobby supplies (for instance, glue) are toxic.
Be aware of which things are toxic. Somethings can be more dangerous in combination. For instance, bleach and ammonia are both toxic, but useful when used carefully. However, when combined (or cleaners containing each are combined), they can create several very dangerous and potentially deadly compounds, including chlorine gas (harmful when breathed), nitrogen trichloride and hydrazine (potentially explosive with other, bad, potential effects too).
Medicine is another common household item, which is necessary and usually beneficial to the people who are supposed to take it, that can be dangerous.
Other sources of toxins include plastics and many furniture finishes. If possible let these "air" outdoors before bringing them inside where they can contribute to indoor pollution.
- BBC article on The Dangers of Mixing Bleach and Ammonia
- About.com on First Aid for Mixing Bleach and Ammonia
- Snopes.com (the Internet rumor investigator) has an article on the Cocoa Mulch Danger to Dogs
- dog owner's digest on Chocolate and Dogs -- Why chocolate poisons dogs and how to treat chocolate dog poisoning
- suite101.com on Chocolate in Dogs and Cats - A Common Pet Poison: Why Chocolate is Dangerous, Possibly Deadly for Dogs & Cats
- the Green Wikia on How To Get Rid of Toxics in Your Home, Toxins in Household Cleaning Products, and Toxins in Personal Care Products
- 8 known carcinogens to remove from your house on Shine by Yahoo!