Hand sprayer use may, without care, expose an applicator to repeated sub-lethal doses of pesticide. The valve trigger may have a tiny leak and if gloves are not also checked for leaks, an applicator’s hands may be exposed to spray. Such exposure is of particular concern with organophosphate pesticides. Check the trigger valve and gloves at regular intervals. Routine cholinesterase testing should be done to check whether an applicator has had exposure, if using organophosphates.