Introduction Machines and processes in the metal industry produce noise levels that are harmful to the human ear if not properly controlled. Empirical studies are lacking to document noise exposure which is one of the stepping stones towards development and enforcement of policies, and standards on noise control in developing countries, including Tanzania where this is lacking.

Methods The study was conducted from June 2016 to June 2017. Full-shift noise measurements (LAeq) were taken by personal dosimeters (Brüel and Kjaer type 4448) in four metal factories in Tanzania (Factory A; 47 measurements, B; 47, C; 34 and D; 40). Workers were randomly selected from payroll and shift list and assigned into job groups; Melters, moulders, firemen, tongsmen, roughing, cutters and pushers.

Results Personal noise exposure varied both within and between factories. The average noise exposure was 91.6 dB(A) in factory A, 96.7 dB(A) in factory B, 93.7 dB(A) in factory C and 89.9 dB(A) in factory D. The moulders had the lowest noise exposure (87.3 dB(A)), followed by melters (89.9 dB(A)), pushers (91.6 dB(A)), tongsmen (93.7 dB(A)), roughing (94.2 dB(A)), firemen (94.5 dB(A)) and cutters/bundlers (98.1 dB(A)).

Discussion To our knowledge this is the first study in East Africa to document personal noise exposure levels in metal industries. The noise exposure exceeded the occupational exposure limit used by OSHA, Tanzania. This study is expected to serve as an important input towards the development of the country’s own regulations regarding noise exposure at the workplace.