Nitrate — formed when nitrogen mixes with oxygen in water — is colorless, odorless and tasteless, and can easily go undetected if water isn’t tested, especially in old wells installed prior to current codes. Nitrogen is a common component of commercial fertilizer and animal manure used on crop land, and can leach into the groundwater.
In a petition filed in April, environmental groups asked the U.S. Environmental Protection Agency to use its emergency powers under the federal Safe Drinking Water Act to intervene in what they call an “imminent and substantial endangerment to human health.” | 
