Iowa Greenhouse Applicators' Perceptions and Use of Personal Protective Equipment

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Greenhouse cultivation of plants may include five growth cycles annually and may require the use of several different pesticides. Waldron reported that greenhouse crops may have pesticide applications on a 3-day cycle (1). Applicators and workers are exposed to pesticides, through application processes and contact with benches and plants during handling or trimming.

Nigg's research review concerning reentry for agricultural workers noted the effect of environmental conditions on pesticide exposure, including contact with foliage and fruit residues, but cited no research about greenhouses (2). The exposure hazard is potentially higher in a greenhouse than outdoors partly because natural dilution occurs outdoors. Poorly ventilated greenhouses may pose a threat to both workers and applicators (1,2,3).

Brouwer et al. studied secondary contamination of applicators and workers from transfer of pesticide residues from sprayed carnations in greenhouses. In some instances employees working with sprayed plants were at a higher risk of exposure than applicators. The authors noted higher than expected incidence of skin disorders on hands of workers (4). Lander and Lings found that cholinesterase enzyme (ChE) activity decreased as weekly spraying time increased among greenhouse workers. They found that gloves were helpful in preventing ChE inhibition (5).

Lander et al. investigated pesticide exposure of greenhouse workers and the effect of using protective gloves during cultivation of flowers in greenhouses. They did not find that gloves helped prevent up-take of anti-ChE pesticides (6). Lander and Hinke studied the effect of PPE on greenhouse worker exposure. They found that the frequency of application and the use of protective clothing were related to ChE inhibition, but found no significant relationship between ChE inhibition and the use of protective gloves or face masks. Whole body protection (coveralls) seemed to prevent skin absorption and reduce secondary contamination from residues on plant leaves, benches, and equipment. They concluded that greenhouse workers not using PPE probably run considerable health risks (7).

Putnam et al. reported reduced pesticide exposure with use of rubber gloves, but concluded that gloves did not completely eliminate exposure when working with vegetable crops treated with nitrofen (8). Lavy, Mattice, and Flynn (9) reported that work habits affect dermal exposure and that contaminated gloves and footwear serve as a continuing source of exposure when workers wear them after chemical use. Despite mixed evidence concerning the efficacy of PPE, Pesticide Applicator Training (PAT) manuals emphasize use of PPE, especially gloves, as a means of reducing exposure (10).

Stone et al. surveyed farm pesticide applicators and found they did not vary their clothing according to the toxicity of the chemicals used (11). A 1991 survey showed that 90% of farm applicators "nearly always" wore or "planned to wear" chemically resistant gloves for mixing and loading pesticides. Fewer of these farmers reported poisoning symptoms than in the earlier study. This was attributed partly to more emphasis on PPE and personal hygiene in educational certification programs (12, 13). Greenhouse applicators were not included in these Iowa surveys.

Attitudes of pesticide applicators and handlers have been studied because PPE cannot provide benefit if workers are unwilling to use PPE correctly (14,15,16,17,18). Stone and Shelley classified Iowa farmers' attitudes about pesticides according to four dimensions: net benefit users, cautious users, understanding/control users, and fatalistic users. They found that farmers were more certain about the benefits of pesticides for crop production and the benefits of PPE than about the health risks involved with pesticides (16). No studies of greenhouse workers' attitudes were identified.

The Worker Protection Standard for Agricultural Pesticides (WPS) specifies that PPE be used according to pesticide label requirements making employers responsible for employee compliance (19). …