Toxic Tort Legal Glossary: N

National Emissions Standards for Hazardous Air Pollutants: Emission standards set by EPA for an air pollutant not covered by NAAQS that may cause an increase in deaths or serious, irreversible, or incapacitating illness. Primary standards are designed to protect human health, secondary standards to protect public welfare.

National Priorities List: EPA's list of the most serious uncontrolled or abandoned hazardous waste sites identified for possible long-term remedial action under Superfund. The list is based primarily on the score a site receives from the Hazard Ranking System. EPA is required to update the NPL at least once a year. A site must be on the NPL to receive money from the Trust Fund for remedial action.

Negligence: Failure to exercise the care toward others which would reasonably be expected of a person in the circumstances, or taking action which a reasonable person would not.

Neoplasm: An abnormal growth or tissue, as a tumor.

Neuro-toxicity: Exerting a destructive or poisonous effect on nerve tissue.

Nitrification: The process whereby ammonia in wastewater is oxidized to nitrite and then to nitrate by bacterial or chemical reactions.

Nitrogen Dioxide: The result of nitric oxide combining with oxygen in the atmosphere; major component of photochemical smog.

Non-Attainment Area: Area that does not meet one or more of the National Ambient Air Quality Standards for the criteria pollutants designated in the Clean Air Act.

Non-Binding Allocations of Responsibility: Process for EPA to propose a way for potentially responsible parties to allocate costs among themselves.

Non-Conventional Pollutant: Any pollutant which is not a statutorily listed or which is poorly understood by the scientific community.

Non-Point Source: Diffuse pollution sources (i.e., without a single point of origin or not introduced into a receiving stream from a specific outlet). The pollutants are generally carried off the land by storm water. Common non-point sources are agriculture, forestry, urban, mining, construction, dams, channels, land disposal, saltwater intrusion, and city streets.

Non-Potable: Water that is unsafe or unpalatable to drink because in contains objectionable pollution, contamination, minerals, or infective agents.

Nutrient Pollution: Contamination of water resources by excessive inputs of nutrients. In surface waters, excess algal production is a major concern.