Investigation of Health Effects Potentially Related to Paladin® (Dimethyl Disulfide) Applications in Hillsborough County, Florida, 2014

Tuesday, June 16, 2015: 3:00 PM
107, Hynes Convention Center
Prakash R Mulay , Florida Department of Health, Tallahassee, FL
Philip Cavicchia , Florida Department of Health, Tallahassee, FL
Antonio Tovar-Aguilar , Florida Department of Health, Tallahassee, FL
Sharon Watkins , Florida Department of Health, Tallahassee, FL

BACKGROUND: In August and September 2014, the Florida Department of Health (DOH) received several complaints of health effects following a strong chemical odor in Hillsborough County. The odor was later confirmed to be from a newly approved soil fumigant, Paladin®. Paladin® contains dimethyl disulfide (DMDS) as the active ingredient and has a sulfurous odor. Since the odor threshold for DMDS is much lower than levels potentially affecting human health, unpleasant odors may occur in and around areas of application. All treated areas must be covered with a plastic tarp to retain the fumigant in the soil. DOH initiated an investigation to better understand the health effects potentially related to the application of Paladin®.  

METHODS: Acute pesticide-related illness and injury is listed as a notifiable disease in Florida. Public Health investigations include surveillance, interviews, medical record reviews, review of supporting documentation (e.g., partner agency investigation reports), and determination of case status. DOH has adopted guidelines from the National Institute of Occupational Safety and Health’s (NIOSH) Sentinel Event Notification System for Occupational Risk (SENSOR) Program to classify cases. Locations of the application sites and residential addresses for all interviewed individuals that indicated home exposure were mapped using Google Earth.

RESULTS: Among the 33 households contacted, DOH interviewed 66 individuals complaining of health effects related to the Paladin® application. The most common symptoms reported by the individuals interviewed included eye pain and irritation, sore throat, cough, dyspnea, nausea, vomiting, dizziness, chest pain, and fatigue. Of the 66 individuals interviewed, 59% matched the case definition for a suspect case of pesticide-related illness and injury, but none were confirmed. Thirty-seven cases were classified with a low severity of illness and two cases were classified with a moderate severity. Mapping data revealed that the average distance of a household from an application site was 1.74 miles. Fifteen percent of households were within 0.25 miles of an application site, 30% were within 0.5 miles, and 48% were within 1 mile. 

CONCLUSIONS: To our knowledge, this is the first report of an investigation of health effects potentially associated with application of Paladin®. Given that we were unable to confirm any cases of pesticide illness and injury from our investigation, we are unable to conclude that Paladin® did or did not cause the health effects reported. Findings from this investigation will help inform activities and preparations taken by DOH for future applications of Paladin®.