This study was set out to investigate the emission characteristics of HCl (in both particle (HClp) and gaseous (HClg) forms), and Cl2 during the trichlorosilane (TCS) burning process under various relative humidity conditions (RH; range = 55%–90%) which might exist at its storage area. All experiments were conducted in a test chamber. We found that HClp was consistently as the most dominant contaminant (= 1.30 × 105–1.46 × 105 mg/m3), followed by the HClg (= 9.03 × 103–11.4 × 103 mg/m3) and Cl2 (= 1.91 × 103–2.18 × 103), emitted from the TCS burning process for the all selected RH conditions. The particle sizes of HClp fell to the range of the accumulation mode (MMADs = 0.808–1.04 μm; GSDs = 2.13–3.50). Fractions of emitted HClp reaching to the alveolar region (= 85.8–88.8%) were much higher than that of the tracheobronchial region (= 6.53–8.80%) and head region (= 4.67–5.40%). It is concluded that more ill-health effects on the deep lung region can be expected than other regions as workers exposed to the contaminants emitted from TCS burning processes.