6 - 
1n Individual exposures, potentially long Induction-latency period from 
beginning of exposure to appearance of effects, and uncertainty as to the 
effects that say occur. Most Importantly, the Group recognizes that medical 
surveillance can never replace the establishment of appropriate physical 
containment of recombined microorganisms and their products* and proper work 
practices as the primary defenses against occupational exposure and disease. 
Nevertheless, the Group has concluded that medical surveillance of workers 
engaged in commercial applications of biotechnologies can play a valuable 
auxiliary role In protecting worker health. Medical surveillance. In Its 
essence, provides a means for evaluation of the effectiveness of physical and 
biological containment In protecting worker health. Also It is the most 
direct means for early Identification of unsuspected adverse consequences of 
occi 4 >ational exposure. It Is therefore the opinion of the Working Group that 
the establishment of medical surveillance programs for biotechnology workers, 
as for workers in any new industry, constitutes prudent medical practice. 
The Working Group considered three potential hazards of biotechnology In 
relation to medical surveillance: microbial hazards, product hazards and 
reagent hazards. 
MICROBIAI. HAZARDS 
Under current working conditions, the health hazard of occi4>at1onal exposure 
to genetically altered microorganisms appears to be slight. Many 
*The level of physical containment of microorganisms used In biotechnologic 
applications must be appropriate for their level of pathogenicity.^ 
[ 513 ] 
