LAER standards are required when a new stationary source is located in a non-attainment air-quality region.
When a BACT is determined, factors such as energy consumption, total source emission, regional environmental impact, and economic costs are taken into account.
In Ohio, between 1970 and 1977, a rule in the Clean Air Act required a reduction in the measured sulfur dioxide (SO2) emitted by coal-fired power plants.
The result was that the SO2 was carried in the wind out of the state and there was a reduction in the measured SO2 in the area near the source.
[citation needed] In the 1977 amendments to the Act, Congress restricted the use of tall smokestacks as a means to attain compliance in SIPs.