This letter transmits preliminary results of a acute toxicity test indicating neurotoxic effects to male and female rats for alkynyl chloride. Undiluted alkynyl chloride was administered as a single oral dose (gavage) to three groups of six male and six female rats at dose levels of 500, 1000, or 1500 mg/kg of body weight. Clinical signs indicative of neurotoxicity (i.e., ataxia, fasciculations, prostration, salvation, lacrimation, tremors, nystagmus and/or dragging of hind limbs) were observed among survivors and decedents at all dose levels. These signs were noted beginning at one hour and continued through day 7. Dose related mortality occurred in this study 0/6 males and 3/6 females at 500 mg/kg; 3/6 males and 6/6 females at 1000 mg/kg; and 6/6 males and 6/6 females at 1500 mg/kg. All deaths occurred by day 3 post-dosing. The test substance, as received, was applied to the shaved intact skin of three groups of six male and female rats at 400, 1200 or 3600 mg/kg body weight. The application sites were occluded for 24 hours.