Four kinds of transition metal based organophosphorus hybrids are synthesized via facile chemical precipitation and employed as flame retardant additives for polystyrene (PS). With the incorporation of 6.0 wt% CoPPI, NiPPI, FePPI and LaPPI, the peak heat release rate (PHRR) values are decreased by 33.2, 25.9, 37.5 and 31.8%, respectively, indicating the improved flame retardancy. The dramatic suppressions on CO release are also observed. When 6.0 wt% CoPPI, NiPPI, FePPI and LaPPI are added, the reductions on peak CO yield (PCOY) are 50.9, 42.3, 343 and 23.9%, respectively, indicating the markedly decreased fire toxicity. Moreover, the obviously decreased peak smoke production rate (PSPR) values and smoke density are observed after their incorporation. In addition, the release of decomposed volatiles is also inhibited by these hybrids, according to the thermogravimetric analysis/infrared spectrometry. Therefore, both flame retardancy reinforcement and toxic effluent elimination of PS are achieved, indicating the enhanced fire safety. (C) 2018 Elsevier B.V. All rights reserved.