many known but remote fields were not being developed. On-site conversion to liquid fuels are making this energy available under present market conditions. Fischer Tropsch fuels plants converting natural gas to fuel, a process broadly known as gas-to-liquids are operating in Malaysia, South Africa, and Qatar. Large direct conversion coal to liquids plants are currently under construction, or undergoing start-up in China. Total global synthetic fuel production capacity exceeds , and is expected to grow rapidly in coming years, with multiple new plants currently under construction. Known adverse health effects Unconventional oil drilling, like unconventional gas drilling, has degraded air quality, contaminated groundwater, and increased noise pollution. Such drilling has also been found to correlate with poor fetal growth and a higher preterm birth rate for residents who live near drilling sites. Gas flaring, which is a common industry practice, releases a toxic mix of harmful chemicals, including benzene, particulates, nitrogen oxides, heavy metals, black carbon, carbon monoxide, methane and other volatile organic compounds, sulfur dioxide and other sulfur compounds, which are known to exacerbate asthma and other respiratory disease. Just three areas together are responsible for 83% of known unconventional oil extraction site flares, unconventional gas extraction site flares and fracking flares in the contiguous United States, and approximately a half million Americans, disproportionately African-Americans, Native Americans, and other people of color, live within five kilometers of these three areas. Environmental concerns As with all forms of mining, there are hazardous tailings and waste generated from the varied processes of oil extraction and production. Environmental concerns with heavy oils are similar to those with lighter oils. However, they provide additional concerns, such as the need to heat heavy oils to pump them out of the ground. Extraction also requires large volumes of water. The environmental impacts of oil shale differ depending on the type of extraction; however, there are some common trends. The mining process releases carbon dioxide, in addition to other oxides and pollutants, as the shale is heated. Furthermore, there is some concern about some of the chemicals mixing with ground water (either as runoff or through seeping). There are processes either in use or under development to help mitigate some of these environmental concerns. The conversion of coal or natural gas into oil generates large amounts of carbon dioxide in addition to all the impacts of gaining these resources to begin with. However, placing plants in