College of Physicians & Surgeons of Columbia University | New York, N. Y. 10032 
DEPARTMENT OF MICROBIOLOGY 
701 West 168th Street 
December 21, 1979 
Dr. Donald Frederickson 
Director 
National Institutes of Health 
Bethesda, MD. 20205 
Dear Donald: 
I write again to express my strong support for the new Guidelines 
recommending a downgrading of containment requirements for most 
E. coli K12 host-vector systems. Ibis is really a rather con- 
servative recannendation, but perhaps it is the best that 
would be acceptable at this time. Ibis recaimendation would 
certainly save investigators and local biohazard biosafety 
committees considerable time, and hence it would be of great 
value to everyone. I heartily endorse these recamiendations 
and sincerely hope that you will approve than. 
With warm personal regards and best wishes for a Happy Holiday 
Season , I remain , 
Yours very truly, 
/can 
Harold S. Ginsberg, M.D. 
Chairman 
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