It's not rocket science -- it's common sense. You should never work with hazardous materials, such as pesticides, without being prepared. So before you rush out to spray your perfectly cut lawn with the latest insect warding chemicals, do your homework.
If mixing chemicals to produce a specific pesticide, always work in a well-ventilated area. Breathing in these harmful vapors can affect your body, creating a "high" that may be a simple as dizziness, but could lead to kidney, liver or nervous system damage.
The Environmental Protection Agency (EPA) has a lot of useful information regarding pesticides and pesticide poisoning. First off, never use more pesticide than directed. Keep your skin covered and avoid contact with the chemicals. This means wearing impermeable gloves as well as long pants and sleeves. Don't apply pesticides in the rain or wind, when the chemicals can be transported to undesignated areas [source: EPA].
When storing pesticides, make sure you've got the proper containers. Place them high up where children and animals can't be exposed to them. This also prevents any damage to the containers if flooding occurs, which could spread the chemicals and cause contamination.
Before disposing of any large quantities of pesticides, contact your local Department of Natural Resources -- they'll be able to direct you of how to do so properly. Keep in mind that open dumping or burning is usually illegal.
If you're concerned about pesticide poisoning, the next page should offer some helpful information.