The Evaluation of Hydrogen Cyanamide-Related Inquiries to the New Zealand National Poisons Centre Between 1990 and 2006

Introduction: Hydrogen cyanamide (Hicane) is a plant growth regulator used in New Zealand to induce bud break in kiwifruit. In early spring of each year (August and September), the agricultural community can use as much as 216 tonnes. The aim of this study is to evaluate the calls received by the New Zealand National Poisons Centre (NPC) regarding Hicane and ascertain the effect of exposure on agricultural workers and those living in close proximity to its area of use. Method: A retrospective analysis of all Hicane-related poisoning inquiries to the NPC was undertaken for the years 1990 to 2006. Results: The NPC received a total of 145 Hicane-related calls; 47 requested information and the remaining 98 involved poison exposure (30 were animal related and 68 were human). Almost all calls were logged during August and September of each year. From 1990 to 1998, the NPC only received 1 to 2 calls per year, but this substantially increased to 17 in 1999, and peaked in 2003 with 26 inquiries. Subsequently there has been a steady decline in inquiries. In humans, most calls on exposure concerned inhalation (54%) and skin contact (28%). The majority of reported symptoms were only mild to moderate; these included nausea and vomiting (29%), headache (22%), contact dermatitis (19%), and erythema (17%). Surprisingly, only 8% of calls received involved alcohol. Conclusion: This study suggests that despite its extensive use, workplace exposure to Hicane has not posed a major threat to health. This may in part be due to education on its use that includes the importance of abstaining from alcohol. There is also no indication that spray drift represents any health threat to the public.