It is the time when cotton plants are sprayed and the insecticide used is a poisonous chemical from the pyrethroid family. Although pyrethroid compounds are well known for not leaving any residue in the environment after 24 hours, the farm worker's burning sensation, caused by the insecticide, is unpleasant. "It stings!"

However, the worker only began spraying half an hour ago. This evening, when he gets home, his face will still be swollen. Tomorrow, the puffiness will disappear. This is one of the health effects of pesticide exposure. Although some pesticides are considered highly effective, killing a variety of insects in less than 10 minutes if direct contact is made, the products have been declared harmful for users who do not take necessary precautions.

According to the Chinese Institute of Occupational Medicine, the unpleasant facial burning sensation experienced by cotton workers, is only one of the symptoms of exposure. The sprayers also complain of nausea, dizziness, headaches, and fatigue. In some more serious cases, involuntary muscular contractions and convulsions are observed, demonstrating that the product is can affect neurological functions.

A study conducted among Chinese farm workers in 1989, recommended that all farm workers receive a structured questionnaire, based on the World Health Organization (WHO) pertinent standards. The workers were monitored for three days following the spraying. Everyone who showed symptoms underwent clinical examinations that included blood and urine tests.

Statistics indicate that more than 80 percent of small holder farmers in Africa, use small pressure sprayers. Simple in design, these sprayers are carried on the back, have one nozzle and are activated with a hand pump. Some research results also indicate that the farmers (sprayers) were not taking the necessary precautions for handling the chemicals.

A good percentage of these farmers have some knowledge of the dangers to which they are exposed to and the toxicity of the chemical products. But some of them spray doses exceeding the manufacturer's recommendations. The inaccuracte of dosages is partly explained by the fact that farmers use the cap of the bottle rather than a proper measuring cup when mixing the pesticide with water.

According to information from the "Clinical Manifestations and Diagnosis of Acute Pyrethroid Poisoning" in China, after a day of spraying in a cotton field, 70 percent of workers were completely soaked in pesticides.

"This is hardly surprising," says the study. "The farmers do not take any precautions when they spray. More than two-thirds of them walk between the rows of plants and spray in front of them. Inevitably, they are sometimes spraying into the wind. As they move down the rows, they come into direct contact with sprayed plants. Few of them wears groves or a mask and more than 25 percent of the spraying equipment leaks because of inadequate nozzles or defective parts."

Although it is known that the contamination is caused by product contact with the skin, most of the sprayers do not were socks, they spray with bare heads, do not were sandals or long sleeved-shirts.