"The water supply of more than 2 million Californians has been exposed to harmful levels of nitrates over the past 15 years -- a time marked by lax regulatory efforts to contain the colorless and odorless contaminant, a California Watch investigation has found.
Nitrates are now the most common groundwater contaminant in California and across the country.
A byproduct of nitrogen-based farm fertilizer, animal manure, wastewater treatment plants and leaky septic tanks, nitrates leach into the ground and can be expensive to extract.
The problem affects both rural Californians and wealthier big-city water systems. State law requires public water systems to remove nitrates. Many rural communities, however, don't have access to the kind of treatment systems available in metropolitan areas.
Nitrates have been linked to 'blue baby syndrome,' which cuts off an infant's oxygen supply. Some studies have found connections to certain cancers in lab animals."