In 1968 the North American Air Defense Command (NORAD) submitted a requirement to the Deseret Test Center to "determine the effectiveness of disseminating pathogenic microorganisms in either dry or wet form from a single or multiple line source at altitudes of 20-50 thousand feet in low temperatures".¹ The requirement was based on NORAD observations of Soviet bomber aircraft with heated bomb bays making flights at altitudes of 20,000 to 50,000 feet approximately 300 miles off the west coast of North America. Primary consideration was given to the vulnerability of the North American continent to a biological attack originating 300 miles off the west coast at high altitude. ²Two contractors, each well-noted in the field of diffusion meteorology, analyzed the effectiveness of disseminating pathogenic microorganisms at high altitude. The results were subjected to a critical in-house analysis by the Deseret Test Center.³ Analysis led a consensus judgement that a high altitude release of biological warfare materials would pose no significant or predictable threat.⁴ It was further concluded that additional research to refine this position would be of little value.⁵ No actual high altitude release of biological simulant was conducted and NORAD’s requirement was considered closed.

¹ Letter, North American Air Defense Command, Ent AFB, CO, 19 June 1968, subject: NORAD Chemical Test Requirements (U).
² High Altitude Release, Special Study in Support of DTC Test 70-D, August 1972, p.1-1.
³ High Altitude Release, Special Study in Support of DTC Test 70-D, August 1972, p.iii.
⁴ High Altitude Release, Special Study in Support of DTC Test 70-D, August 1972, p.iii.
⁵ High Altitude Release, Special Study in Support of DTC Test 70-D, August 1972, p.1-1.