Radiological Hazard: A source of actual or potential danger to a person(s) which occurs or
could occur because of exposure to radiation.
Recommended Exposure Limit: The NIOSH equivalent of OSHA PELs and ACGIH TLVs to
be used in the absence of PELs and TLVs.
Rescue Service: Offsite personnel designated to rescue employees from permit spaces, or other
hazardous areas when the onsite rescue team is not available.
Site: An area where physical work is being performed and where the potential of exposure to
protective clothing and/or respirators.
Site-Specific Training: Predefined training, unique to a particular site.
Spill: The uncontrolled release of a hazardous substance into the environment that onsite
personnel are capable of containing. Distinguished from a major spill.
Standard Entry Procedure: A procedure for entry into confined spaces which utilizes the
complete array of entry measures. It is characterized by use of trained personnel, atmospheric
testing before and during entry, use of proper protective equipment, and completion of the entry
Storage: The temporary placement of a hazardous material in a location which provides some
protection to personnel or the environment.
Support Zone: Uncontaminated area where workers are unlikely to be exposed to hazardous
substances or dangerous conditions.
Task: A well defined unit of work having an identifiable beginning and end with two or more
elements. A task is a series of jobs performed in support of a particular project.
Threshold Limit Value (TLV): An exposure limit established by the American Conference of
Governmental Industrial Hygienists (ACGIH) under which most people can work consistently for
8 hours a day, day after day, with no harmful effect.
Threshold Limit Value-Short-Term Exposure Limit (TLV-STEL): The concentration to
which workers can be exposed continuously, for a short period of time, without suffering from
irritation, chronic or irreversible tissue damage, or narcosis, provided that the daily TLV-TWA is