PVC catalyst ethyl chloroformate -- delayed edema

[ttweed@wildrockies.org (Tony Tweedale)]

G T Bowra(*), 'Delayed Onset of Pulmonary Oedema following Accidental
Exposure to ethyl chloroformate'  _J. Soc. Occup. Med._ 31:67-8 ('81)

(*) chief medical officer, Mond Div. of ICI ltd.

says e.c. is a highly volatile liquid used as a catalyst in the manuf. of
PVC., presumably in the polimerization step.  after a hose disconnected a
worker was splashed w/ it (wearing PVC apron & full-face fresh air mask),
and inhaled fumes from discarded contaminated clothes in the shower-heated
room he showered in.  3.5 hours after the incident he developed tight chest
and dififculty in breathing.  Apparantly he developed water in the lungs
(edema) around then, he was treated w/ frusemide (?) and steroids, and
perfusion returned to normal.  No fibrosis.
---

my comments:  3.5 hrs--not what I'd call delayed edema, but no matter,
except that no indication is given of the length of follow-up (see next
p'graph).  Respired irritants--microbial, particles (inert or not),
chemicals--set off the immune system's inflamation Rx, in which a lot of
proteins are produced that variously engulf, attack w/ free radicals, etc.
the foreign agent, the by-product of all which includes redness, swelling
and fluid ("inflamation").  Treatment is w/ anti-inflamatory agents such as
steroids or non-steroidal anti-inflammatory drugs (NSAIDS) such as aspirin
& ibuprofin, all of which suppress the immune system..  A side effect of
the inflamation Rx is apparantly is increased ischemic heart disease--heart
attacks & strokes--possibly caused by the thickening of the blood that
occurs when the immune system is activated (inflammation).  E.g., there is
a clear association between respirable particulate matter (PM2.5 microns)
and heart attacks & strokes.

As to chronic effects of pulmonary irritants (including Cl2 gas & ClO2),
another function of the immune's inflamation Rx is the classic allergen
theory, i.e. the immune's putting a unique chemical tag (antibody) on the
foreign agent (antigen), for future quicker and stronger response.  I.e.,
next time you are exposed to a significantly lower amount of the
sensitizing agent--possibly much smaller dose--you will activate your
immune response and suffer an inflamation Rx all over again.  Some
chemicals, such as the isocyanates release by U. Carbide at Bhopal, are
known as cross-sensitizers, i.e exposure to them will make you react to
lower doses of OTHER foreign agents.  This is the most common theory of the
mechanism of multiple chemical sensitivity (MCS).  Dr. Wlm Meggs has also
observed that the normally tight junctions between the epithelial cells
lining the airway are opened up 5 years after an acute ClO2 exposure,
possibly allowing foreign agents & chemicals another route into the inner
body.

Tony Tweedale

Causality is a concept not subject to empirical demonstration. -David Hume
(1711-'76)

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