Pesticides regulating auxin growth did not appear to increase the risk of HL. When the pesticides evaluated by mode of action were stratified by home versus work use, ORs were greater in magnitude for work-related exposures, in particular for the acetylcholinesterase inhibitors (using three or more in the younger than 40 age group OR 11.15, 95 % CI 1.15–108.2). When excluding proxy respondents from analyses by mode of action, the direction of effect remained the same, and for most exposure groups, the magnitude of the odds ratios increased.