Professional Evaluation of Occupational Chemical Exposure in Pharmaceutical Manufacturing Plants in Ogun State

Pharmaceutical manufacturing workers in Ogun State, South West Nigeria, are potentially exposed to a range of chemical agents including active pharmaceutical ingredients, solvents, excipients, and airborne particulates, yet occupational exposure monitoring programmes in Nigerian manufacturing facilities are rarely documented in scientific literature. This study evaluated occupational chemical exposure in three pharmaceutical manufacturing facilities in the Agbara industrial estate, Ogun State. Personal air sampling was conducted for nine hours across production shifts for workers in formulation, coating, and quality control departments. Target analytes included ethanol, isopropyl alcohol, methylene chloride, ethyl acetate, acetone, and airborne dust. Samples were collected on charcoal tubes and particulate filters, and analysis was performed by gas chromatography and gravimetric methods respectively. Ethanol concentrations in the coating department reached 680 ppm, approaching the OSHA permissible exposure limit of 1,000 ppm. Methylene chloride was detected at concentrations of 18 to 94 ppm in formulation areas, with the NIOSH recommended exposure limit of 25 ppm exceeded in 30 percent of personal samples. Respirable dust exceeded 10 mg/m3 in tablet compression operations. Heat stress co-exposure was a significant concern in non-air-conditioned manufacturing areas. Engineering controls such as local exhaust ventilation were adequate in only one of three facilities. The study recommends regular occupational hygiene monitoring, improved engineering controls, biological monitoring for methylene chloride-exposed workers, and health surveillance programmes as components of a minimum occupational safety standard for Nigerian pharmaceutical manufacturers.

Keywords: occupational chemical exposure, pharmaceutical manufacturing, methylene chloride, personal air sampling, Ogun State