defocused group of construction works help each other written job hazard analysis jhs risk assessment confined space

analysis assessment atmosphere australia background black blue business carbon closeup concept confined construction danger defocused design desk detector device each education emissions environment equipment foreground gas greenhouse group hand hazard help hydrogen industrial industry isolated jhs job mining monoxide nature officer other paper park people protection restricted risk safety sensor sign site space sulfide table technology test tester tool uniform welding when worker working works written yellow