Attachment I, i^e 5 
surveillance might play in the detection of any disease or dysfunction which 
might be caused by occupational exposures to microorganisms containing rDNA or 
their products. The Working Group recognizes that neither the extent nor the 
severity of any health hazards which may be associated with such exposures are 
known. The Group realizes further that the eff ectiveness of medical 
surveillance will inevitably be limited by such factors as the relatively 
small size of most groups under study, variability in individual exposures, 
long induction- latency from beginning of exposure to appearance of effects, 
and uncertainty as to the effects sought. Most importantly, the Group 
recognizes that medical surveillance can never replace the appropriate 
physical containment of recombinant microorganisms and their products as the 
first line of defense against exposure and disease.* Nevertheless, the Group 
has concluded that the medical surveillance of workers engaged in commercial 
applications of rDNA technologies can play a valuable auxiliary role in 
protecting worker health. It is therefore the opinion of the Group that the 
establishment of medical surveillance programs for rONA workers constitutes 
prudent medical practice. 
MICROBIAL HAZARDS 
Under current working conditions the health hazard of exposure to 
microorg»iisms containing rDNA appears to be slight.®’^ The majority of the 
•The level of physical containment of microorganisms used in recombinant DNA 
applications must be appropriate for their level of pathogenicity.^ 
[ 383 ] 
