This study investigated the hypotheses that occupational exposure to acid mists is positively associated with periodontal disease, assessed by periodontal attachment loss. The study sample included 530 male workers at a metal processing factory. Data were obtained from interviews and oral examinations. Periodontal attachment loss was defined as > 4mm at probing, in at least one tooth. A job exposure matrix was utilized for exposure evaluation. Exposure to acid mists was positively associated with periodontal attachment loss > 4mm at any time (prevalence ratio, PRadjusted = 2.17), past (PRadjusted = 2.11), and over 6 years of exposure (PRadjusted = 1.77), independently of age, alcohol consumption, and smoking, and these results were limited to workers who did not use dental floss. Exposure to acid mists is a potential risk factor for periodontal attachment loss, and further studies are needed, using longitudinal designs and more accurate exposure measures.