Criteria. A whole body dose of 25 rem (0.25 Sv) is generally accepted as
a dose that will not cause early health effects (that is, health effects that
manifest themselves within a few hours or days of irradiation).
The use of CEDE instead of TEDE may be nonconservative because it
does not include external irradiation, if any. However, the predominant
means of potential exposure at most U.S. nuclear facilities (i.e.,
nonreactor facilities) is through the inhalation of long-lived alpha emitters,
from which there is a very small contribution to external irradiation. In
general, therefore, the use of CEDE is approximately equivalent to the
use of TEDE.
Hazardous material exposure - Emergency Response Planning Guideline
Level 2 (ERPG-2), as established by the American Industrial Hygiene
Basis: The ERPG-2 is "The maximum airborne concentration below
which it is believed that nearly all individuals could be exposed for up to
1 hour without experiencing or developing irreversible or other serious
health effects or symptoms that could impair an individual's ability to take
protective action." This guideline has clearly been developed as a
threshold for emergency response and has been used in a number of
regulatory situations (e.g., by agencies that administer the State of
California's Risk Management and Prevention Program). The use of
ERPG-2 also has precedent in DOE's Emergency Management Guide for
Hazards Assessment, where it is chosen as a protective action guideline.
Hazardous materials where ERPG-2 has not been established - the Level
of Concern (LOC) as established by the U.S. Environmental Protection
Agency (EPA), as specified in the 1987 EPA Technical Guidance on
Hazards Analysis (or a successor document).