Aluminium workers are exposed to a complex mixture of airborne chemicals. Workers in different stages of aluminium manufacturing are exposed to different mixtures of chemicals. At twelve US aluminium facilities, we used information from an industrial hygiene database containing 30 years of sampling results for 227 separate chemical agents to build job exposure matrices (JEMs). We selected chemicals that represented major exposures in the workplace (e.g., oil mist and fluorides) and those that have been associated with heart disease [e.g., polycyclic aromatic hydrocarbons (PAHs) and welding-related metals]. We used cluster analysis to empirically group the chemical agents and establish exposure profiles by job. For PAHs and welding-related metal exposures, we also built quantitative JEMs. There were 21 PAH chemical agents, including individual PAHs (e.g. benzo[a]pyrene) and groups of PAHs (e.g. coal tar pitch volatiles). For metals, there were 54 different chemical agents associated with welding tasks. The categorical JEMs have three categories of exposure: unmeasured, very low exposure, and moderate or higher exposure. The stage of the manufacturing process made a large impact on the distribution of exposures. While 62% of jobs in smelters involved PAH exposures, only 2% of jobs in fabrication facilities did. Conversely, oil mist exposure is more common in fabrication facilities, compared with smelters (24% and 7% of jobs exposed, respectively). We observed that the exposure profiles in smelters was very different to those observed in fabrication facilities or refineries. These chemical exposure JEMs will help clarify the role chemicals play in heart disease.