Risk factors for occupational illnesses associated with the use of paraquat (1,1'-dimethyl-4,4'-bipyridylium dichloride) in California.
California Department of Food and Agriculture (CDFA) reporting systems were used to describe the characteristics and independent risk factors for reported paraquat (4685147) related occupational illnesses in California, and to develop a method to assess the relationship between the agricultural use of paraquat or other pesticides and the resulting illnesses. The CDFA sources included the Pesticide Illness Case Report (PICRs) for 1971 through 1985 and the Pesticide Data Bank (PDB) concerning paraquat applications in 1984. Pesticide Use Reports (PURs) were also available for 1981 through 1985. In 23.8% of the cases located through PICRs, mention was made of multiple pesticide use. The greatest proportion of illnesses were systemic (38.5%), eye and skin illnesses (32.0 and 26.0%, respectively), and local respiratory symptoms (3.5%). About 41% of the illnesses were in persons younger than 24 years of age. About half of the females involved were working in the manufacture of the chemical. Paraquat related illnesses were reported from 34 counties. Agriculture accounted for 93.5% of the cases. Most of the illnesses, 39.1%, occurred during the handling of spray equipment, either during cleaning or in association with a malfunction while spraying. More than 70% of the local/irritant illnesses resulted from contact with the face and upper extremity. The most common complaints included dizziness, nausea, or lightheadedness, followed by headache, chest pain, vomiting, tiredness, shortness of breath, and burning skin sensations. Of the 231 cases, 55 (23.8%) lost from 1 to 30 workdays. Eleven cases were hospitalized for 1 to 17 days. Three indices of paraquat use were denominators for paraquat associated illness risk: counts of applications, acreage treated, and pounds of paraquat applied. Among the various methods of application, a higher risk was associated with ground application than with aerial application.