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 substances are any materials (in any state-solid, liquid or gas) that have a definite chemical composition. Chemical substances can therefore be. a pure chemical element. a pure chemical compound.This definition and interpretation is generally considered sufficient for school-level, incl GCSE Chemistry.There are, however, some other definitions e.g.  A form of matter that has both definite composition and distinct properties. Chemical substances are any materials (in any state-solid, liquid or gas) that have a definite chemical composition. Chemical substances can therefore be. a pure chemical element. a pure chemical compound.