There are several reasons for high blood lead: 1, industrial pollution, if you work in a heavy industrial environment for a long time, engaged in the production of pigments or chemical production will be prone to high blood lead, chronic lead poisoning, etc. 2, lead-containing gasoline and exhaust pollution, the traditional gasoline supply production of tetraethyl lead as an anti-explosive agent, which will be exhaled into the human body in the form of gas, leading to chronic lead poisoning in the human body. 3, school supplies and toys, such as brightly colored books and freshly printed and dyed picture books, coloring pages contain certain lead elements. Toys, such as brightly colored books and freshly printed and dyed picture books, colorful pages will contain certain lead elements, if prolonged, large amounts of contact will appear certain high blood lead. 4, food additives, such as prolonged, large amounts of intake of puffed food will also lead to high blood lead.