In steel industry, hard coal is proceeded in coke ovens to produce metallurgical coke. In this process, some additives such as petroleum coke (petcoke) are used for optimizing operational cost. For the determination of addition ratio of petcoke, it is important not to disrupt coke quality, especially with respect to coke reactivity index and coke strength after reaction, while another important point is emission quality. In this study, petcoke gas (PCG) emitted from the thermal decomposition of petcoke at the maximum thermal decomposition temperature is characterized for volatile organic compounds (VOCs) and polyaromatic hydrocarbons (PAHs) and the results are assessed in comparison to the coke oven gas (COG). First, the petcoke sample is heated for gasification by using thermal gravimetric analyzer-DTA device. The gas in the temperature range of 490-510 degrees C, where the highest gasification acceleration occurs, is taken from the funnel and transferred to GC-MS device by using a headspace gas sampler unit. The total VOC concentration in PCG and COG is found to be 121.76 ppm and 5,774.76 ppm, respectively, while the total PAH concentrations are 0.625 and 0.495 ppm, respectively. The results show that using petcoke in coal blend seems to be a more environment-friendly process with respect to a significant decrease in VOC emissions.