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1 exposures. In one chemical plant, for example, 90 of 
2 12 S workers had abnormal liver function tests. 
3 These situations exist despite the fact that 
4 worker exposures are to chemicals whose effects are at 
5 least reasonably predictable, and in some cases, reversible; 
6 despite the fact that both environmental and relevant 
1 biological monitoring techniques are available; despite 
g the fact that OSHA regulations are applicable; and despite 
g the fact that the workers are represented by a strong 
10 union. 
11 In contrast is the situation that exists with 
12 regard to worker exposure to recombinant DNA material. One, 
13 the nature and reversibility of the effects of worker 
14 exposure to recombinant DNA molecules are unknown and 
15 in many cases unpredictable. And in fact, the effects 
16 of exposure to the attenuated organisms containing the 
17 recombinant DNA material are unknown. For example, a 
18 prospective study of the ability of the "benign” E. col i 
19 K 12 to colonize the urinary tract of exposed laboratory 
2q workers has not yet been done. And yet, El. col i is 
21 responsible for 70 to 80 percent of urinary tract 
22 infections in this country, and such infections afflict 
23 five percent of the general medical clinical population. 
24 Urinary tract infections are a major source of bacteremias 
25 in this country, and kill from 66,000 to 165,000 people 
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