Background and aims: Melamine is a chemical widely used in the industries .It was used in the production of plastic – coated plates, glue, molding compounds and melamine dinnerware. Formaldehyde as an irritant was produced in the melamine dinnerware production and create some health problem. In this study irritant risk assessment of formaldehyde was assessed in Melamine dinnerware industry.

Methods: In this study 54 workers were selected from melamine dinnerware workshops as exposed groups. 30 workers from dairy production workshops was evaluated who were not occupationally exposed to irritants. The personal monitoring of workers was performed according to the NIOSH method No. 3500.Irritant effects of formaldehyde were evaluated using HSE/HSL questionnaire .Relative risk was calculated for each response.

Results: Mean occupational exposure of workers to formaldehyde was 0.1±0.044 ppm. The results of Chi-square test showed in the exposed group irritation of respiratory tract and eyes was higher than controls (P<0.05). Also relative risk of all irritation effect was more than 1.Maximum eye irritation was evaluated by pressing workers when formaldehyde exposure was more than others.

Conclusion: Occupational exposure of workers to formaldehyde was higher than the respective NIOSH Threshold Limit Values–Time Weighted Average (TLV-TWA).It seems, irritation of respiratory tract and eyes occur in the lower concentration of formaldehyde TWA of Iran standards. Due to irritation relative risk in the melamine dinnerware workshops, a program of risk management required.