From The Eclectic Gardener @ www.teachinggarden.org
Written by Alan Hickman

Lucrezia Borgia may or may nor have deserved her reputation for poisoning inconvenient people but, as an educated member of a rich and powerful Renaissance family, she certainly would have been aware of the lethal potential of plants. It is really only in the past fifty years that there has grown up a naive belief that things which are called 'organic'or 'natural'or 'pure'are products which will do no harm.
When I was a boy my father used to keep all his cigarette butts in a box. When the roses got attacked by green fly or the cabbages were beset by caterpillars, he'd soak a handful of butts in water and spray the plants with the resulting gucky brown solution. Half a century later, on a garden phone-in broadcast by CBC, a caller earnestly explained how she had purchased a pound of raw tobacco in the States and was using it to make an organic pesticide spray for her houseplants. In a similar vein, last spring, I was talking to one of Brampton's property inspectors. He told me he'd been on holiday in Cuba and how progressive he thought the Castro regime was in its organic agricultural practices. The farmers there, he said, use ground-up tobacco to spray on the crops.
Apart from my father - who used his old fag-ends because they didn't cost anything - all these people really thought they were doing something good for the environment by using something organic, ergo safe, and not using nasty 'chemicals'. It didn't seem to occur to any of them that nicotine, the active ingredient in these home-brew concoctions, has proven to be so toxic and so hazardous to humans that it is not registered in Canada for use as a domestic pesticide.
A tragic result of the use of nicotine as an insecticide was related to me a couple of weeks ago by a neighbour. When Jim was in school, the father of one of his classmates operated a commercial greenhouse near the corner of Queen Street and Kennedy Road - 1st Line East as it was then. One day the boy noticed a half-full bottle of Coke in the greenhouse and took a swig of the contents. Unfortunately it wasn't cola in the bottle; it was nicotine spray and the boy died soon thereafter.
When it comes to the risks of everyday life, as a result of having neither the time nor the inclination to question what passes for 'common sense', people often make very bad choices.
For a start, the distinction between toxicity and hazard needs to be understood. Toxicity is the ability of a substance to injure; hazard is the probability that the circumstances of exposure are such as to produce injury. Sounds complicated but a simple example of the difference between toxicity and hazard goes as follows: if you go to the tundra, a thousand kilometers from the nearest habitation, and dig a hole six feet square and six feet deep, the chance that anyone will fall into it and hurt themselves is, at most, slight, i.e. the hazard is very low. Dig the same hole outside Hooters on a Saturday night and the hazard would be very high. Put a fence around the hole or cover it with a sheet of steel and the hazard would again be very low. The hole (the toxicity) is always the same but the potential for harm changes with the circumstances.
For regulatory purposes, substances are grouped by class and people are often aghast when they discover where the things they use every day fit in.
In one system toxicity is graded on a rising scale from 1 to 6. Class 1 substances are 'Practically Non-Toxic'and include food and talc. Class 2, 'Slightly Toxic', includes: most cosmetics, some insecticides and milk of magnesia. Class 3, 'Moderately Toxic', covers: hair dye, bleach and kerosene. Class 4, 'Very Toxic', includes: disinfectants, aspirin and many agricultural chemicals. At seminars when this list is read out, there is usually an audible gasp when people hear that aspirin is rated as a very toxic substance along with agricultural chemicals. Class 5 is 'Extremely Toxic'and covers drain cleaners, antihistamines - usually another gasp - and some pesticides. Finally, the most extreme poisons and carcinogens, Class 6, 'Super Toxic', is home for: a few commercial pesticides, strychnine, cyanide and our 'natural', 'organic'friend nicotine!
It is perverse but true that well-meaning people, who likely support the banning of relatively safe and low hazard Class 2 domestic pesticides, are the very same people who promote the use of a highly toxic, cancer-causing, Class 6 substitute.