(environmental impacts) Fly ash is a cocktail of unhealthy elements – silica, aluminum, iron oxides, calcium, magnesium, arsenic, mercury, and cadmium, and poses serious environment and health hazards for a large population. But the brick is better off, for flyash changes into a non-toxic product when mixed with lime at ordinary temperature as the calcium silicate hydrates and forms a dense composite inert block. Thus having the potential as a good building material, while offsetting about 100million tonne’s of flyash annually produced in India by the numerous thermal power plants, which could cause serious contamination of land, groundwater and air.