The second page of the tabbed Agents form is the Exposure Assessment page. The information
on this page was selected to help the clinician estimate the dose received by
the exposed worker. Recommended maximum air concentrations in ppm are shown
for TLV, STEL and Ceiling (ACGIH); PEL (OSHA); MAK (Federal Republic of
Germany); and IDLH (Immediately Dangerous to Life or Health from NIOSH). The
user can click the toggle button to convert to mg/m3 values and click it again to
convert back to ppm.
Vapor pressure X 1300 is an estimate of the saturated concentration of the chemical after a spill in a confined space at room temperature.
(See "Solvent Vapor Pressure and Health Hazards" in Sullivan,
p. 1086-7.) For example, a chemical with a VP of 380 mmHg would be expected to
reach a concentration of 0.5 million ppm, and one with a VP of 760 mmHg could
reach a concentration of a million ppm (760 X 1300 = 1,000,000). Styrene has
the potential to reach a concentration of 6500 ppm after a spill in a confined
space. This concentration is higher than both the IDLH and the LC50.
is the maximum concentration from which, in the event of respirator failure, one could escape within 30
minutes without experiencing any escape-impairing or irreversible health
effects. The LC50 is the 30-minute exposure concentration at which half of the
experimental animals are likely to die (from lack of oxygen to the brain
induced by anesthesia for the case of styrene). The RD50, an estimate
of severe respiratory irritation, is the 10-minute exposure concentration producing a 50% respiratory rate reduction in
mice or rats. The NFPA flammability code of 3 indicates that styrene may
ignite at ambient temperature. See Chemical Hazard
Scores for an explanation of "Exposure Points" and "TIH."
The third page presents the potential adverse effects of styrene exposure.
Like other solvents, styrene can disrupt brain function causing fatigue and
lightheadedness at lower doses and inebriation and anesthesia at higher doses.
ACD is an abbreviation for allergic contact dermatitis, while PACD
and PICD stand for photoallergic and photoirritant contact dermatitis.
An "Uncoupler" is a chemical like pentachlorophenol that can
cause a hypermetabolic state by poisoning cellular respiration (uncoupling
oxidative phosphorylation). A Hematotoxin is a chemical that can cause
methemoglobinemia, aplastic anemia or hemolytic anemia.