Methemoglobinemia: An Industrial Outbreak Among Rubber Molding Workers

Abstract

This case series documents an occupational outbreak of methemoglobinemia among five steam press operators at a rubber plant. Investigative findings identified the cause as repeated exposure (through manual handling) to an adhesive containing dinitrobenzene. The workers presented with yellow-stained hands and a variety of clinical manifestations. Methemoglobinemia levels obtained in the emergency room ranged from 3.8% to 41.2%. Methylthioninium chloride (methylene blue) rapidly reversed the cyanosis and alleviated associated symptoms in the rubber molding workers requiring treatment. Prompt action by plant officials and subsequent investigation by National Institute of Occupational Safety and Health/Occupational Safety & Health Administration personnel resulted in the timely and successful resolution of the problem. Individual presentations, assessment, and management are discussed along with recommendations for occupational investigation and referral.