N/D
NOT DETERMINED

NA
NOT APPLICABLE

NAAQS
NATIONAL AMBIENT AIR QUALITY STANDARDS

NACD
NATIONAL ASSOCIATION OF CHEMICAL DISTRIBUTORS

NACE
NATIONAL ASSOCIATION OF CORROSION ENGINEERS;  NORTH AMERICAN COMMISSION ON THE ENVIRONMENT

NACR
NATIONAL ASSOCIATION OF CHEMICAL RECYCLERS

NAE
NATIONAL ACADEMY OF ENGINEERING

NAEM
NATIONAL ASSOCIATION FOR ENVIRONMENTAL  MANAGEMENT

NAEP
NATIONAL ASSOCIATION OF ENVIRONMENTAL  PROFESSIONALS

NAFTA
NORTH AMERICAN FREE TRADE ACT

NAM
NATIONAL ASSOCIATION OF MANUFACTURERS

NAMF
NATIONAL ASSOCIATION OF METAL FINISHERS

NAPAP
NATIONAL ACID PRECIPITATION ASSESSMENT PROGRAM

NAPCTAC
NATIONAL AIR POLLUTION CONTROL TECHNIQUES  ADVISORY COMMITTEE

NAS
NATIONAL ACADEMY OF SCIENCES

NASA
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION

NASP
NATIONAL AEROSPACE PLANE

NCCA
NATIONAL COIL COATERS ASSOCIATION

NCMS
NATIONAL CENTER FOR MANUFACTURING SCIENCES

NCP
NATIONAL CONTINGENCY PLAN

NCRIC
NATIONAL RESPONSE AND INFORMATION CENTER

NDCEE
NATIONAL DEFENSE CENTER FOR ENVIRONMENTAL  EXCELLENCE

NDE
NONDESTRUCTIVE EVALUATION

NDT
NONDESTRUCTIVE TESTING

NEA
NATIONAL ENERGY ACT

NEAF
NORTH AMERICAN ENVIRONMENT FUND

NEC
NATIONAL ELECTRICAL CODE

NEHA
NATIONAL ENVIRONMENTAL HEALTH ASSOCIATION

NEPA
NATIONAL ENVIRONMENTAL PROTECTION ACT

NESHAP
NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR  POLLUTANTS

NETA
NATIONAL ENVIRONMENTAL TRAINING ASSOCIATION

NFIB
NATIONAL FEDERATION OF INDEPENDENT BUSINESSES

NFPA
NATIONAL FIRE PROTECTION ASSOCIATION

NGO
NONGOVERNMENTAL ORGANIZATIONS

NGV
NATURAL GAS VEHICLES

NGWA
NATIONAL GROUND WATER ASSOCIATION

NIDI
NICKEL DEVELOPMENT INSTITUTE

NIE
NATIONAL INSTITUTE FOR THE ENVIRONMENT

NIEHS
NATIONAL INSTITUTE OF ENVIRONMENTAL HEALTH  SCIENCES

NIMBY
NOT IN MY BACKYARD

NIOSH
NATIONAL INSTITUTE FOR OCCUPATIONAL SAFETY AND  HEALTH

NIPDWS
NATIONAL INTERIM PRIMARY DRINKING WATER  STANDARDS

NIPERA
NICKEL PRODUCERS ENVIRONMENTAL RESEARCH  ASSOCIATION

NIST
NATIONAL INSTITUTE FOR STANDARDS AND  TECHNOLOGY
(FORMERLY NATIONAL BUREAU OF  STANDARDS)

NIWR
NATIONAL INSTITUTES FOR WATER RESOURCES

NMAB
NATIONAL MATERIALS ADVISORY BOARD

NOAA
NATIONAL OCEANIC AND ATMOSPHERIC  ADMINISTRATION

NOC
NOT OTHERWISE CLASSIFIED

NOEL
NO OBSERVABLE EFFECT LEVEL

NOI
NOTICE OF INTENT

NOS
NOT OTHERWISE SPECIFIED

NOV
NOTICE OF VIOLATION

NOx
NITROGEN OXIDE

np CHART
This is a special type of the p CHART where the number of nonconformance
is tracked from a fixed sample size at  each instance.    EXAMPLE:  Number of
rejects found in a lot inspection with equal sample size at each inspection.

NPCA
NATIONAL PAINT AND COATINGS ASSOCIATION

NPDES
NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM

NPDWR
NATIONAL PRIMARY DRINKING WATER REGULATIONS

NPL
NATIONAL PRIORITIES LIST (SITES)

NPP
NATIONAL PRETREATMENT PROGRAM

NR
NOT REQUIRED

NRC
NATIONAL RECYCLING COALITION; NATIONAL RESEARCH  COUNCIL; NATIONAL RESPONSE CENTER

NRD
NATURAL RESOURCE DAMAGES

NRDC
NATIONAL RESOURCES DEFENSE COUNCIL

NREP
NATIONAL REGISTRY OF ENVIRONMENTAL  PROFESSIONALS

NRT
NATIONAL RESPONSE TEAM

NSF
NATIONAL SCIENCE FOUNDATION

NSPE
NATIONAL SOCIETY OF PROFESSIONAL ENGINEERS

NSPS
NEW SOURCE PERFORMANCE STANDARDS

NSR
NEW SOURCE REVIEW

NSSS
NATIONAL SEWAGE SLUDGE SURVEY

NSWMA
NATIONAL SOLID WASTES MANAGEMENT ASSOCIATION

NTIS
NATIONAL TECHNICAL INFORMATION SERVICE

NTP
NATIONAL TOXICOLOGY PROGRAM

NTSC
NATIONAL THERMAL SPRAY CONFERENCE

NTTC
NATIONAL TECHNOLOGY TRANSFER CENTER

NTU
NEPHELOMETRIC TURBIDITY

NVLAP
NATIONAL VOLUNTARY LABORATORY ACCREDITATION  PROGRAM

NVR
NONVOLATILE RESIDUE