Pesticide use around a rural medical centre associated with health problems in patients and staff.

On a morning of July 1999, the lawn of a rural medical facility was sprayed with an organophosphate (Chlorpyrifos) without any warning to staff and patients. Patients waiting to enter the building were exposed due to proximity of spraying and windy conditions. A physician walked through a cloud of spray. Details about the concentration of pesticide used were not available but use of a high concentration was probable. Exposure was suspected to have continued inside the building through opened windows, air exchanger, and people movements through the doors. Within one to two hours all the staff experienced different levels of eye, throat and skin irritation, dry burning lips, metallic taste, nausea, lightheadedness, headaches, chest tightness and difficulty concentrating. People were too sick to return to work in the afternoon and had to leave the next day after two hours in the building. During the following days, the physician most exposed experienced increased symptomatology and one asthmatic person bringing a patient was severely affected. Discontinuation of patient services, extensive and costly cleaning followed. The most affected physician kept experiencing symptoms upon reentry into the building and took a month of sick leave. The second physician also experienced symptoms inside the building. Inspection of the building showed an inadequate ventilation system and presence of carpets in heavily used areas that may have exacerbated the problem. Recurrence of symptoms among the staff and in some sensitive patients raised questions about safety of the building. Open discussion about options, further cleaning and improvements took place. Testing for residual levels of Chlorpyrifos in air and swab samples was negative. The most affected physician re-experienced symptoms after cleaning of ventilation ducts. Six months after the initial event, there is no complaint outside some very sensitive patients who experience symptoms. This event showed that affected individuals may continue to experience symptoms after initial exposure due to a combination of factors, and that such events could have been easily prevented.