14 
LX. CDC-NIH GUIDELINES AND NCI REVISION OF ONCOGENIC VIRUSES GUIDELINES 
Dr. Barkley said the Centers for Disease Control/National Institutes of 
Health (CDC/NIH) Interagency Working Group had completed a draft of guide- 
lines entitled "Biosafety in Microbiological and Biomedical Laboratories." 
He noted that the document had been distributed widely for comment, and that 
fewer than two dozen responses, mostly favorable, had been received. It 
appears that after a long and arduous process, consensus has been achieved. 
The working group is considering adding a section dealing with how one might 
use the principles contained in the document to assess the hazards of 
organisms not already included and a section dealing with how one judges 
the operational integrity of biological safety cabinets. 
Dr. Barkley said the CDC/NIH document recognizes that the principal 
route of infection among laboratory workers is auto-inoculation and direct 
contact contamination, e.g., finger or hand contact with contaminated 
surfaces and subsequent contact with mucous membranes. Ingestion is no 
longer a hazard in the laboratory with the elimination of mouth pipetting. 
Most agents listed in the document are grouped in the level comparable to 
the P2 level of containment. Dr. Barkley explained that these agents were 
grouped together since the same techniques, essentially good laboratory 
practices, are used to interrupt the route of infection. 
Dr. Barkley said the CDC/NIH guidelines recognize that only a few human 
pathogens are capable in the laboratory situation of presenting risk frcm 
direct inhalation, e.g., the agents causing Q fever and TB. The higher 
containment levels are reserved for this type of agent. This is not to 
suggest that aerosol control per se is not important in laboratory safety. 
Indeed, aerosol control is important not only in attempting to reduce 
inhalation exposure but more importantly in reducing the dissemination of 
materials to other laboratory surfaces which offer greater opportunity for 
hand to mouth or nose contact. 
Dr. Barkley said the CDC/NIH document designates four levels of control: 
Biosafety Levels 1, 2, 3, and 4. These levels are comparable to PI, P2, 
P3, and P4 in the NIH Guidelines for Research Involving Recombinant DNA 
Molecules. Agents such as those causing Q fever and TB are grouped in 
Biosafety Level 3. Biosafety Level 4 is reserved for exotic pathogens for 
which there is currently no means of disease control such as Lassa fever. 
Dr. Barkley said the philosophy on which the document "Biosafety in Micro- 
biological and Biomedical Laboratories" is based is similar to the philosophy 
new being used to revise the National Cancer Institute "Safety Standards 
for Research Involving Oicogenic Viruses" (October 1974). [>:. Barkley said 
that although that review is not complete, the recommended control level 
for all cancer viruses including Human T-cell Leukemia-Lymphoma Virus 
(HTLV) will be Biosafety Level 2. 
[198] 
