The chemicals that farmers use to kill weeds pose hidden dangers to people, animals and the environment. While herbicides help to increase the food supply and boost the economy, they also contribute to pollution and illnesses ranging from skin irritation to cancer. Understanding the pros and cons of herbicides can help you make more informed choices about the produce you buy, businesses you choose to support and the types of products you use to maintain your lawn.

Left untended, weeds compete with crops for water, sunlight and nutrients in the soil. Using herbicides eliminate this competition to allow for greater crop yield, fewer food shortages and lower food prices. From 1965 to 1990, the use of herbicides and pesticides doubled the yield of the world's eight most common crops, reports the Weed Science Society of Pakistan. Without herbicides, the use of some crops, like carrots, would be cut by nearly 50 percent each year.

A 2013 report by the Delta Farm Press estimates that the use of herbicides provides a $16 billion boost to farmers in the United States each year. Herbicides cut weed control costs by $10 billion, including more than $1 billion in savings in hand weeding alone. Farm Chemical International reports that the use of herbicides in Argentina provided a $30 billion boost to the country's struggling economy.

While it's tough to put a price on a well-manicured golf course or a blooming garden, these types of beautiful landscapes offer benefits of their own. Without herbicides, golf courses and sports fields would likely be filled with weeds, and homeowners would find it more difficult to maintain flower beds and vegetable gardens.

Chemical herbicides pose health dangers for everyone from field workers to people who buy food grown using these chemicals. Exposure to herbicides causes skin irritation, while inhaling these chemicals irritates the throat and nasal passages. Herbicide exposure is also linked to non-Hodgkin lymphoma, reports the Northwest Center for Alternatives to Pesticides, and even birth defects in unborn babies.

Farmers who rely on herbicides find that they have to keep using more and more of these chemicals to keep weeds at bay. Weeds demonstrate a remarkable ability to adapt to these chemicals and resist their effects. This resistance increases herbicide costs for farmers and results in a larger quantity of herbicides in the soil.

Chemical herbicides contribute to air, water and soil pollution. Not only do they pollute the soil where they have been applied, but rainwater can carry these chemicals to other areas. Some chemical herbicides end up in waterways, where they kill fish and other aquatic life, according to a study published in the Japanese Journal of Veterinary Research. Chemical herbicides can also evaporate into the air, resulting in air pollution and reduced air quality.