Methemoglobinemia: an industrial outbreak among rubber molding workers

Area of Science:

• Occupational Health
• Toxicology
• Environmental Medicine

Background:

• Occupational outbreaks of methemoglobinemia can occur in industrial settings.
• Exposure to aromatic nitro compounds, such as dinitrobenzene, is a known cause of methemoglobinemia.

Purpose of the Study:

• To document an occupational outbreak of methemoglobinemia among steam press operators.
• To identify the causative agent and exposure route.
• To describe the clinical presentation, management, and resolution of the outbreak.

Main Methods:

• Case series documentation of five affected workers.
• Investigation of the rubber plant environment and work practices.
• Clinical assessment including methemoglobin level measurement.
• Treatment with methylthioninium chloride (methylene blue).

Main Results:

• Five steam press operators developed methemoglobinemia from manual handling of an adhesive containing dinitrobenzene.
• Clinical signs included yellow-stained hands and cyanosis.
• Methemoglobin levels ranged from 3.8% to 41.2%.
• Methylthioninium chloride rapidly reversed cyanosis and symptoms.

Conclusions:

• Occupational exposure to dinitrobenzene in adhesives can cause methemoglobinemia.
• Prompt investigation and intervention are crucial for outbreak resolution.
• Effective management includes prompt diagnosis and treatment with methylene blue.
• Recommendations for occupational investigation and referral are provided.