Gas-phase emissions from 3D printers have received widespread attention with respect to their health risk. Here, we characterize the formation of gaseous emissions from polymer filaments. Analysis of gases released from different types of 3D filaments was performed on commercially available materials. The composition of gaseous mixtures was monitored, as well as the dependence of the gases on temperature and time. The thermal decomposition of material in an air stream equipment was used to formation of gaseous emissions. Experimental temperatures were determined according to the filament manufacturer's technical documentation. The analysis of the composition of gaseous products was performed on an FTIR spectrometer and the results corresponded to data from the literature. In one case, acetonitrile was detected, which was not expected to be present. Furthermore, it was found that the composition of gas-phase emissions and the time dependence of gas-phase emissions differ according to the composition of filaments. The identified dependencies allow the proper identification of health hazards when using 3D printers. In particular for newly developed filaments, it is necessary to evaluate the composition of the gaseous products of thermal decomposition of material in order to be able to take measures to ensure safety.