THIS BUILDING SAFE TO OCCUPY?
response to schools and public occupancies
(The 10 PPM
Department of Health Hydrocarbon Evacuation Recommendation)
By:Joseph A. Cocciardi,
PhD. MS CSP
Response teams and individuals performing Health Hazard investigations
(Health Inspectors, Fire and Safety Inspectors) are many times called to
School and Public Building occupancies. Typical responses are for hydrocarbon
releases, hydrocarbon based chemical spills,
or "Unknown Source"
odors, with individuals complaining of symptomatic exposures.
Tests are run on
site, and many times follow up environmental testing is performed. Initial
tests are compared to levels identified as Immediately Dangerous to Life
or Health (less than 19.5% O2, greater than 20% of the lower explosive
limit of a combustible vapor), and other on site testing, such as those
tests performed with organic vapor analyzers or length of stain testing
equipment, are performed.
Initial tests show
NO Immediately Dangerous to Life or Health (IDLH) atmospheres, yet symptoms
or odors persist. The question raised by school officials or operators
of public buildings in situations such as this is: IS THIS BUILDING
SAFE TO OCCUPY?
Typically, test data
collected on site by HAZMAT or Health Hazard personnel is compared to a
variety of standards. These include the Permissible Exposure Limits
(PEL) developed by the US Department of Labor, Occupational Safety and
Health Administration; the Recommended Exposure
by the US Public Health Service, Centers for Disease Control and Prevention:
National Institute for Occupational Safety and Health (NIOSH) ; or those
of other groups with recommendations in this area, such as the American
Industrial Hygiene Association (AIHA) or the American Conference of Governmental
Industrial Hygienists (ACGIH).
however, are designed to protect the occupational population, typically
adults over the age of 18. It is these individuals who are allowed
by law to work in dangerous environments. The levels cited do not and are
not designed to protect at risk populations such as children in schools
or the elderly.
these occurrences may next turn to the US Public Health Service: Agency
for Toxic Substances and Disease Registry (ATSDR) published Minimal Risk
Levels (MRL). These levels are designed to serve as a screening tool to
help investigators decide where adverse health
effects are not
likely to occur, and they take into account the most sensitive populations
(children, the elderly and those with compromise immune systems). MRL are
published for acute exposures (less than 2 weeks), for intermediate exposure
( 2 weeks to 1 year) and for chronic exposures
(greater than 1
Many times the chronic
exposure levels are used as re-occupancy criteria by health departments
after the release of hazardous substances, and these are sometimes referred
to as the "walk-away" levels.
at a site which exhibits characteristics above the ATSDR acute risk level
may wish to recommend evacuation for all but brief (which may be construed
as up to two week) exposures.
The dilemma, however,
is this: the ATSDR criteria, and similar criteria published by the
US Environmental Protection Agency (EPA), are re-occupancy or ACCEPTABLE
levels, those at which there is no appreciable risk of an adverse effect
occurring. The question remains, at what levels
be made to evacuate these target occupancies, IMMEDIATELY!
To address this issue,
the Pennsylvania Department of Health has researched and issued guidelines
for the evacuation of schools (and by interpretation, public occupancies
with school age children in them).
These can be found
on the PA Department of Health Website at www.state.pa.health/site, or
by searching the PA Department of Health web site for the "Tools for Schools
" criteria. The PA DOH has RECOMMENDED THE EVACUATION OF SCHOOLS WHERE
10 PPM OR MORE OF TOTAL HYDROCARBONS ARE PRESENT, OR .1 PPM OR MORE OF
BENZENE IS PRESENT. These levels are above the ATSDR minimal risk
levels, but well below the occupational exposure criteria.
relative to toxins in these specialized environments can be found on the
web page as well, such as the re-occupancy criteria for schools after the
release of mercury.
personnel in Pennsylvania, as well as in other jurisdictions who choose
to adopt or reference the PA DOH evacuation criteria, should be prepared
to test on site for total hydrocarbons and benzene to the referenced levels,
and subsequently recommend evacuation of
structures due to
health hazards when these levels are identified.
for the 10 PPM total hydrocarbon level or the .1 ppm benzene level on site,
OR, equipment and tests that are useful when investigating releases or
potential releases of hydrocarbons and unknown odors in SCHOOLS and Public
on this subject can be acquired from Dr.