OSHA Section 9 - IX comments:
there has been concern about potential infectivity of aerosols generated
by dental, medical and laboratory equipment, HBV has not been detected
in such aerosols, and risk is posed primarily by large particles of
'spatter' that travel only short distance.(Tr 9/14/89,p.21)"
- "Aerosols are solid or liquid particles, ranging in size from
submicrometer to multimicrometer, which are suspended in a gas. This
suspension can last from a few seconds to a day or more." p.50
- "The term 'aerosolization'...has been replaced with 'generation of
droplets.'" OSHA Section 9 XI
- "...There has been no documented cases
in the literature...of HIV transmission via aerosols..."
- "...To the best of our knowledge...there have been no cases."
- "...Aerosols are not known to present a risk of transmission of blood
borne pathogens...Therefore, use of respirators for protection against
blood borne pathogens is not recommended.p.50
- "...The current opinion of experts is that, while aerosol transmission
is a theoretical possibility, it does not contribute measurably to
- "...There are no known instances...nor are other instances known in
which airborne particles containing bloodborne pathogens have presented
a risk to health care workers."p.50
- "CDC/NIOSH...Aerosols are not known to present a risk of transmission of
bloodborne pathogens in the healthcare environment. There are no
- "aerosol" should not be used in the same context as splatters and
OSHA intends a distinction between "droplets" and "aerosols"
to make it clear that "droplets" "spatters" "splashes" (such as produced
by power saws and drills) are of concern, not 'aerosolization' (as produced
by ultrasonics), neither by airborne respiratory transmission or as evidence
of contamination of environmental surfaces by aerosolization.
"Splattering of blood onto skin or mucous membranes of the face and upper
respiratory tract against large droplet splattering is needed. ...glasses,
goggles, face shields, and surgical masks...as appropriate to the task being
performed, can provide that protection."OpCit p.51
Pseudo-scientists put some "marker-dye" in an ultrasonic and
observed the "marker dye" was aerosolized and deposited on
surfaces away from the ultrasonic. They concluded that covering
that ultrasonics was necessary to limit the spread for pathogens and protect
the worker. Their
experiment was faulty and their conclusions were false.
- The emphasis by OSHA is to encourage the establishment of procedures that
prevent the initial problem before focusing on protection.
"Paragraph (d)(2)(xi) requires that all procedures involving blood or
other potentially infectious materials shall be performed in such a
manner as to minimize splashing, spattering, and generation of droplets
of these substance . . . will also reduce contamination of surfaces
e.g., benchtops, instruments) in the general work area"
- "Assuming a 'worst case' of a single virion infectivity and knowing the
capability of minute aeosols to remain suspended in air and therefore
spread widely throught the facility, respiratory protection would be
necessary for essentially every person within the facility. However, if
such a situation were true, the Agency would expect seroconversion rates
to be drastically increase among those exposed; but this does not appear
to be the case." Summary, p.52"
"The hierarchy of controls provision, paragraph (d)(2)(i), of this
standard requires employers to implement engineering controls and work
practices prior to relying on personal protective equipment for protecting
employees against exposure" OSHA