本文结合鞍钢实例,初步探讨了新建、改建、扩建工程项目时,保证安全生产和捎除有毒有害物质的设施与主体工程同时设计、同时施工,同时投产(即“三同时”)的必要性,以及应当抓住的三个关键环节. Based on the example of Ansteel, this paper discusses the necessity of simultaneously designing, constructing, putting into production (ie, “three simultaneousities”) at the same time to ensure the safe production and removal of toxic and hazardous substances at the time of new construction, reconstruction and expansion project. As well as the three key points that should be grasped.