Radiation levels there are still normal and not harmful to human health, a ministry spokeswoman said.

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Burning diesel versus gas results in higher levels of nitrogen compounds and soot, both of which can be very harmful to human health.

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Drug concentrations in water are not thought to be harmful to human health, although concerns remain over possible effects on plant and animal life.

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The Environmental Protection Agency consistently ranks hazardous-waste sites as less harmful to human health than radon, outdoor particulate pollution or working exposure to pesticides.

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The Medicines and Healthcare Regulatory Authority, which oversees medicines in the UK, said that any product containing the drug was considered "harmful to human health".

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These substances are harmful to human health and local air quality.

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In Pennsylvania for example, the Department of Environmental Protection (DEP) has found that there are no emissions from Marcellus shale activities that reach levels harmful to human health.

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The government has had some success targeting primary pollutants, but analysts say it is just beginning to target secondary pollutant problems, including particulate matter that is harmful to human health.

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The rule targets equipment that power plants and manufacturing facilities use to draw in water to prevent overheating, even though those intake systems are not harmful to human health or water quality.

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