How long does marijuana stay in your system of you smoked it once? Someone who smokes occasionally-or for the first time-will  likely test positive for 1-3 days afterward, according to a review  by the  National Drug Court Institute (â¦ NDCI).ow long does marijuana stay in your system of you smoked it once? Someone who smokes occasionally-or for the first time-will  likely test positive for 1-3 days afterward, according to a review  by the  National Drug Court Institute (â¦ NDCI).
Chemical hazard. A chemical hazard is a type of occupational hazard caused by exposure to chemicals in the workplace. Exposure to chemicals in the workplace can cause acute or long-term detrimental health effects.
Chemical hazards. The use of chemicals has increased dramatically due to the economic development in various sectors including industry, agriculture and transport. As a consequence, children are exposed to a large number of chemicals of both natural and man-made origin.