What is being done about manganese exposure causing manganism?
Researchers are still investigating the link between welding rod
fumes and manganism. Welding rod litigation has now begun to
help those who suffer the ill health effects of welding and
manganese exposure.
Efforts are being made to reduce the risk of
environmental manganese exposure. In 1994, the U.S. Environmental Protection
Agency (EPA) denied a petition by Ethyl Corporation to allow the
use of methylcyclopentadienyl manganese tricarbonyl (MMT) in
unleaded gasoline, because of health concerns related to the
inhalation of manganese fumes (Davis, 1999).
Other environmental laws have been enacted to limit manganese
exposure and welding fume toxicity. However, some scientists
feel that more needs to be done about manganism and welding
fumes. Researchers studying the health effects of welding fumes
report a "preponderance of proof for manganese neurotoxicity"
even in present-day industrial settings (Iregren 1999).
According to the U.S. Department of Labor Mine Safety and Health
Administration, Welding Fumes Sampling is required due to the
"potential hazards of welding operations including metal fumes,
toxic gases, and ultraviolet and infrared radiation. Fume
particles are formed from vaporization of molten metal. They are
very fine in size, generally one micron or smaller, and may join
together to form larger particles. Welding fumes can be sampled
by drawing air through a special filter at a controlled rate.
"The adverse health effects of welding exposure include chronic
or acute systemic poisoning, metal fume fever (a short-term
painful ailment with symptoms of fever and chills),
pneumoconiosis (lung disease due to accumulation of mineral or
metallic particles), and irritation of the respiratory tract.
"The welding fumes produced at welding operations depend
primarily on the composition of the metals being welded and the
welding rods. When the base metal is iron or steel, with welding
rods of similar composition, the main component of the welding
fume will be iron oxide. When welding on stainless steel,
welding fumes containing nickel and chromium may be produced.
Welding on plated, galvanized or painted metals may generate
fumes containing cadmium, zinc oxide or lead. In addition,
welding rods can generate fluoride and free silica in the fumes,
depending on the composition of the welding rod coating.
"In summary, welding processes may generate many different metal
fumes and other toxic components. It is important that the
hazards of a welding operation be evaluated properly. Toxic
gases that arise in welding include carbon monoxide, nitrogen
dioxides and ozone. If welding or cutting operations are
conducted in the presence of chlorinated hydrocarbons, such as
the form of solvents either on the metals or in the air,
hazardous concentrations of phosgene and hydrogen chloride,
which are highly toxic irritant gases, may be produced.
"In addition to the health hazards of metal welding fumes and
toxic gases, welding operations involve the hazard of burns from
flame, arc, molten metal, heated surfaces and also that of metal
splatter. ...When personal respiratory protection is required,
this may be provided by a supplied-air welding hood or, when the
components and concentration of the fume are known, by a
filter-type respirator with filter for protection against
welding fumes. It is preferable, of course, that adequate
ventilation be provided so as to make the use of respirators
unnecessary.
"When sampling for welding fumes, the inspector will use a
filter cassette placed on the collar or shoulder so that it is
beneath the helmet when the helmet is placed down. The sampling
pump is fastened to the belt. Samples [for welding fumes] may be
full shift or short-term. Short-term samples may be taken to
evaluate toxic [welding fume] components which have short-term
limits. In addition, the inspector may sample for toxic gases
such as ozone, nitrogen oxides or phosgene. It is important that
the welder carry out the welding operation in a normal way, so
that an accurate evaluation of the exposure can be made. The
inspector will attach and remove the filter cassette and pump as
required.
"Normally, good local or general ventilation is required to
control exposures to the metal welding fumes and gases of
welding operations. The most effective control is local exhaust
ventilation in which an exhaust hood is placed near the welding
arc or flame, and the 'welding fume contaminants' are drawn away
from the welder's breathing zone. The system may consist of
moveable exhaust hoods, flexible and stationary ducts, a powered
fan, and a welding fume or dust collector. Exhausted air
containing welding fumes should be discharged to the outdoors,
if possible. It is important that, during the welding operation,
the exhaust hoods are placed or set so that welding fumes are
not drawn across the worker's face or into the breathing zone.
Good general ventilation should be provided. Welding in confined
spaces, such as tanks, cabs of mobile equipment and large
shovels, may be especially hazardous and require additional
ventilation to reduce welding fumes."
About the author:
Michael Monheit, Esquire is the managing attorney for Monheit
Law, located in Philadelphia, Pennsylvania Monheit Law, P.C.
concentrates its practice in the field of plaintiff personal
injury cases on a contingency fee basis. They can be found at
www.monheit.com
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