By their very nature, most pesticides create some risk of harm - Pesticides can cause harm to humans, animals, or the environment because they are designed to kill or otherwise adversely affect living organisms.
At the same time, pesticides are useful to society - Pesticides can kill potential disease-causing organisms and control insects, weeds, and other pests.
Are some pesticides safer than others?
Biologically-based pesticides, such as pheromones and microbial pesticides, are becoming increasingly popular and often are safer than traditional chemical pesticides. In addition, EPA is registering reduced-risk conventional pesticides in increasing numbers.
Read more at the US EPA: http://www.epa.gov/pesticides/about/