LED lights are replacing traditional incandescent and CFL bulbs for their lower energy consumption and miniature size. We see a wide variety of LED use in our day to day life like bulb, rechargeable light, automobile lamp, electronic display, LED TV display, electronic banner, toys etc. We are using them a common household object ignoring their bad sides. The material that are used to produce LED are gallium arsenide (GaAs), gallium phosphide (GaP), or gallium arsenide phosphide (GaAsP). It also contains Lead, Arsenic, zinc or nitrogen, silicon, germanium, and tellurium. Many of these elements have severe health hazard issue. So we should be careful about using them specially in children toys. A study on the impact of LED lights are published here (https://www.scientificamerican.com/article/led-lightbulb-concerns/
) for further reading.