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Report - Health and Safety

Health and Safety Concerns -  - Bag samples - Incomplete results of the bag samples done
on Monday, 3/18 were received today. The compounds listed are the most abundant in the
samples. A complete list is forthcoming. The results indicate that VOC such as benzene,
toluene, xylene, and ethyl benzene are the most common VOC emanating from the cracks in
the road. PAH were not detected at this point. Three sulfide compounds were also detected
in the samples, and there was some concern as to their effect on human health and safety
and respiratory protection. At this point I don't think that the present respiratory
protection guidelines need to be changed, for the following reasons: - Benzene: Benzene
was detected at substantial levels, but since it is only one of many VOCs, a level of 5
PID unit would be protective enough for exposure to Benzene, especially since the exposure
is not continuous. -  - Sulfides: The ratio of VOC to sulfides in the samples collected is
approximately 1 to 0.0001. Based on discussions with LSU, NOAA chemist, and contractor IH,
this ratio should remain fairly stable, since this is what the tire materials is made of,
and there is much more material that can become VOC vapors and gases than sulfide gases.
Assuming that this ratio holds, a VOC level of concern set at 5 PID unit (which
approximate 5 ppm of VOC) would allow for 0.0005 ppm of sulfides. This level is much below
the level of concern for sulfides. It would have been better to monitor directly for
sulfides, but currently no quick direct reading was identified. Relying on VOC as
surrogate will have to do for the time being. - Note: Once conditions change, the level
and composition of sulfur compounds may change as well. If oxygen is introduced when
excavation begins, the sulfur may oxidize to SO2, or other sulfur compounds may form.  -
- More bag samples - So far, protection on this site assumed that the gases and vapors
escaping from the vents are mostly VOC. This assumption was reinforced by the bag samples,
but the detection of other compounds introduced some uncertainty. Collecting more bag
samples would reinforce the assumption that (1) VOC are the main problem and (2) the ratio
between the VOC and sulfides is similar to the two bag samples already collected, and
therefore VOC are sufficient surrogate for sulfides.  -  - Air sampling  - As long as the
workers are potentially overexposed to air contaminants and may need to use respiratory
protection, their work environment needs to be monitored. Air sampling needs to be done
near the workers, to ensure that they are not overexposed. Respirators need to be worn if
the level of concern is exceeded. Sampling does not have to be conducted if workers are
not present on site. Air sampling is done for their protection.  -  - Site control - The
exclusion zone should be clearly marked, so no entry by error and lack of control would be
possible.  -  - Level B entry into the road exclusion zone - Entry into the area of the
cracks in the road should be done in level B only. The high levels of Benzene and CO, as
well as other toxic compounds preclude suing APR at these conditions.  -  - Points to
think about - Excavation may create some problems: -  - Fire: More oxygen to the tire
material may cause a bigger fire and burn. There is a risk that nearby woods will catch
fire as well -  - Vapor and gases: Excavation may release large amount of VOC and other
gases. More oxygen may cause less CO (it will oxidize to CO2) but more SO2 (the sulfide
would oxidize). H2S is not likely to be formed (need to verify this point with LSU and
NOAA chemist) -  - Trapped VOC: Trapped VOC may burn. There is some possibility that
igniting trapped VOC pockets may create an explosion.  -  - Planning ahead - Protection
level may have to increase if the release of VOC and other gases justify that. If level B
is necessary, equipment to support it has to be brought to the site. If large emissions
are possible, the road may have to be closed, and the command post moved. Air modeling
should be made for several scenarios of gas and vapor releases. Once the draft work plan
for excavation is ready, it need to be carefully reviewed to determine the health and
safety implications.