14 
environment. These measures of “physical containment” are grouped 
into four categories, Pi, P2, P3, and P4, each level more stringent 
than the one preceding to correspond to the presumed potential risks 
of various experiments. Fifth, researchers must use biologically weak- 
ened vectors and host organisms that are unlikelv to survive in a non- 
laboratory environment or exchange DXA with other organisms. 
These materials are also graded, EKl, EK2, and EK3, to provide 
“biological containment” commensurate with the potential j-isk of 
harm. Before they can be used in recombinant experiments, EK2 and 
EK3 host-vector systems must undergo extensive testing, review by 
the Recombinant Advisory Committee, and certification by the Direc- 
tor of NIH.Thus, permitted experiments are assigned levels of physi- 
cal and biological containment which are to a degree interchangeable ; 
an increase in biological containment may permit a lowering of phys- 
ical containment requirements. 
EFFECTS OF THE GUIDELINES 
According to testimony before the subcommittee, these measures, 
taken together, provide a high degree of protection of public health 
and the environment. Philip Handler stated the conclusion of the 
National Academy Panel on Risks and Benefits of Recombinant DXA 
Research, whose members included authorities in molecular biology, 
genetics, infectious diseases, and epidemiology. He quoted : 
Currently available evidence leads us to conclude that the many benefits of 
recombinant DXA research and technology can be achieved with negligble risks 
to the biosphere when the work is carried out within the XIH guidelines. 
Despite minor reservations about the permissiveness of the stand- 
ards, Bruce Levin of the University of Massachusetts characterized 
their approach to the unknown risks of recombinant DXA as properly 
one of “extreme prudence.” Paul Berg, Frank Young, Roy Curtiss 
and others generally agreed with this assessment. 
In the past, physical containment procedures similar to those re- 
quired by the XIH guidelines appear to have been effective in pre- 
venting infections from human pathogens used in research. In other 
public testimony, the Director of the Xational Cancer Institute’s 
Office of Research Safety described the experience with high con- 
tainment at the former biological warfare laboratory at Fort Detrick, 
Mel. During a 10-year period ending in December 1969, only one labo- 
ratory-acquired infection occurred as a result of an accidental glove 
puncture. The environmental impact statement accompanying the 
guidelines included an analysis of laboratory-acquired infections data 
from the Center for Disease Control, the National Animal Disease 
Center, and the Xational Institutes of Health as well as Fort Detrick; 
it found no case where a disease was transmitted from an infected 
laboratory worker to another person. The EIS noted that only eight 
such cases have been documented for other American and foreign 
laboratories. In short, scientific research with pathogens under strin- 
gent containment appears to have an excellent safety record. 
Roy Curtiss and others who have attempted to calculate the risks of 
survival and reproduction of a weakened test organism or vector 
should physical containment fail believe that these risks are exceed- 
[Appendix B — 274] 
