16 
VII. PROPOSED MODIFICATION OF P4 CONTAINMENT 
Dr. McKinney began the discussion on modifying the requirements of P4 
containment (tabs 1102, 1107, 1101/1). Dr. McKinney said this topic had 
been broached at the January 21, 1983, meeting of the Working Group on 
Revision of the Guidelines. 
At that meeting. Dr. Malcolm Martin of the NIH suggested Appendix G-II-D-2-a 
of the Guidelines be modified. That section specifies that: 
"Experimental procedures involving organisms that require P4-level 
physical containment shall be conducted either in (i) a Class III 
cabinet system or in (ii) Class I or Class II cabinets that are 
located in a specially designed area in which all personnel are 
required to wear one-piece positive-pressure isolation suits." 
Dr. Martin said the specification requiring use of the Class III glove 
box is meant to protect the investigator against aerosol contamination. 
He said the Class III glove box does not, however, afford protection when 
infection by the organism being studied does not occur by aerosol exposure. 
He argued that automatic assignment of experiments to the glove box ties 
up the staff of the P4 facility, since all manipulations are more difficult 
to perform in the glove box. Dr. Martin suggested the language of Appendix 
G-II-D-2-a be amended to include a statement that: 
"...in those situations where an aerosol will not be generated or 
when illness is not caused by aerosol exposure, the research must 
be conducted in the P4 facility, but options for working outside 
the glove box may be available." 
The Working Group on Revision of the Guidelines agreed language providing 
greater flexibility in use of the P4 facility should appear in the Federal 
Register as a proposed action for a period of comment. After consultation, 
NIH staff determined that Appendix G-II-D-2-c might more appropriately be 
modified. The following proposed modification was published in the Federal 
Register : ~ 
"Appendix G-II-D-2-c. Alternative Selection of Containment Equipment . 
Experimental procedures involving a host-vector system that provides 
a one-step higher level of biological containment than that specified 
can be conducted in the P4 facility using containment equipment require- 
ments specified for the P3 level of containment. Alternative combina- 
tions of containment safeguards are shown in Table II. In those cases 
where the host is an organism which does not cause infection by the 
respiratory route (e.g., use of Eh_ coli K-12 or cerevisiae host- 
vector systems), the local IBC may set appropriate containment for 
procedures within the P4 facility." 
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