Now, if the heavy metal sticks to the ash, stays with the ash, then it may not be so bad because that can be filtered out pretty easily.

NPR: Coal Ash May Pose Health Hazard

The operator should use an independent risk evaluator for weather and other environmental conditions like volcanic ash or even heavy pollutants which can effect helicopter operation and pilot visibility.

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If it gets into the water, into the drinking water, and the heavy metal leaches out of the ash that can be hard to deal with.

NPR: Coal Ash May Pose Health Hazard

The sadhus, many of them naked, dreadlocked and smeared in ash, ran to the river amid heavy security.

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Coal ash contains low concentrations of arsenic, mercury and other heavy metals, although it's not classified as hazardous.

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