China on Thursday ordered manufacturers of potentially toxic products to conduct safety and environmental checks after a recent spate of major anti-pollution protests triggered fears of more unrest. The Asian nation has been hit by two large-scale demonstrations in as many months, sparked by concerns among residents that factories were polluting the environment, forcing local authorities to shut the plants. In the northeastern city of Dalian, for instance, thousands of locals protested last month against a factory that made paraxylene (PX), a flammable carcinogenic liquid used in the production of polyester films and fabrics. \"Manufacturers of sensitive products such as PX and owners of construction projects must immediately start safety and environmental checks,\" said the National Development and Reform Commission (NDRC), the top economic planner. It also called on local authorities to launch inspections of those manufacturers, in a statement released with four other ministries and agencies such as the State Administration of Work Safety, and published online. The NDRC raised the example of Dalian, where people protested after a pollution scare spread when an incoming storm breached a dyke protecting the PX plant and threatened to damage the building. \"Although there were no leaks or other related accidents, it sparked concern about the PX project among some Dalian residents and triggered a mass incident,\" the statement said. \"In recent years, some enterprises have ignored safety production management of hazardous chemical substances, and environmental pollution accidents have occurred... which can lead to mass events.\" Protests against pollution are not new to China, as breakneck economic growth over the past three decades has caused severe degradation of air, land and water quality. But the growth of social networking, in particular Twitter-like \"weibo\" or microblogs, has helped spread the word about environmental issues and mobilise protests against perceived polluters. Earlier this month, more than 500 residents living near a plant making solar panels protested for three days in the eastern city of Haining, forcing authorities to temporarily shut the factory.