Colour and monochrome CRTs contain toxic substances, such as cadmium, in the phosphors.
The rear glass tube of modern CRTs are made from leaded glass, which represent an environmental hazard if disposed of improperly.
By the time personal computers were produced, glass in the front panel (the viewable portion of the CRT) used barium rather than lead, though the rear of the CRT was still produced from leaded glass.
As electronic waste, CRTs are considered one of the hardest types to recycle. CRTs have relatively high concentration of lead and phosphorus, both of which are necessary for the display.
But why cannot CRT’s be dumped into Landfill? Why do they have to be disposed of in a responsible and environmentally friendly way?
Your old TV is considered hazardous waste because it has elements of lead in it.
The lead that’s in our television screens and our computer screens that protects us from the harmful rays from these screens, when they get into landfills and become broken and potentially leech into the environment and the ground and water supply, it’s then that that lead becomes harmful, as does the arsenic, mercury, beryllium and cadmium.