Government Organizations

CCOHS Canadian Centre for Occupational Health and Safety
CDC Centers for Disease Control and Prevention 
DOE U.S. Department of Energy
EPA U.S. Environmental Protection Agency
The Federal Register
NASA National Aeronautics and Space Administration
NIH National Institutes of Health
NIOSH National Institute for Occupational Safety and Health
NSF National Science Foundation
OSHA Occupational Safety and Health Administration
U.S. Department of Health and Human Services
U.S. Patent and Trademark Office

Health and Safety

ACGIH American Conference of Governmental Industrial Hygienists
AIHA American Industrial Hygiene Association
American Health Consultants
CCOHS Canadian Centre for Occupational Health and Safety
CDC Centers for Disease Control and Prevention
Compliance Control Center
NIH National Institutes of Health
NIOSH National Institute for Occupational Safety and Health
OSHA Occupational Safety and Health Administration
SAFELAB Corporation - Consulting firm specializing in laboratory planning, safety and design. There are safety articles and technical publications on this site.
The TrainingNet
U.S. Department of Health and Human Services
World Health Organization

Professional Associations

AAALAC Association for Assessment and Accreditation of Lab Animal Care
AALAS American Association of Laboratory Animal Science
ACCA Air Conditioning Contractors of America
ACS The American Chemical Society
AESP Association of Energy Service Professionals
AIA The American Institute of Architects
The American Institute of Physics
The American Physical Society
The American Society of Engineering Technology
ARI Air Conditioning and Refrigeration Institute
ASCE American Society of Civil Engineers
ASHE American Society for Healthcare Engineering
ASHRAE American Society of Refrigerating and Air-Conditioning Engineers
ASME American Society of Mechanical Engineers
CIBSE Chartered Institution of Building Services Engineers
Engineering Council (UK)
Engineering Foundation
European Physical Society
IEE Institution of Electrical Engineers (UK)
ISPE International Society for Pharmaceutical Engineering
NSPE National Society of Professional Engineers
RSES Refrigeration Service Engineers Society
SEFA Scientific Equipment & Furniture Association
SME Society of Manufacturing Engineers

Standards

ANSI American National Standards Institute
ICBO International Conference of Building Officials
ISO International Organization for Standardization
NEC National Electric Code
NFPA National Fire Protection Association
NIST National Institute of Standards & Technology
NSSN from the American National Standards Institute
UL Underwriters Laboratories Inc.

Trade Publications

The Air Conditioning, Heating & Refrigeration News
Consulting-Specifying Engineer Online
Engineered Systems 
FacilitiesNet
Tradeline Exclusive Reports
HPAC Engineering
The HVAC/R Directory & Source Guide
HVAC Online
Journal of Mechanical Design
Laboratory Design Newsletter
R&D Magazine
The Ultimate Technology Directory