“Didn’t get much work done. Col. Sawyer gave us a very interesting lecture on war gases.”

First Year / Winter Term @ RMC January 1950 – 3069 W.A. McColl


Jan. 20 – 1950: Got a small letter today from Fran. Bob got a food parcel from home which was very good. It is quite cold now and the bay and lake has a thin coating of ice. These days I find it very hard to keep awake after supper, not getting as much work done as I should.


  • Dr. Don Gates, 8035

    January 23, 2012 at 7:01 pm

    We had the same lecture from Col Sawyer in early 1966. It is probably the one single lecture that I enjoyed while at RMC.

    What folks might find interesting is that these equations from RMC’s Col Sawyer were used as the basis for the “Kill Clock” concept in the 2001-2003 Anthrax remediation programs for Hart Senate Building (next to the Capital Building), the Brentwood DC USPS and finally the Trenton NJ US Post Office. I was fortunate enough to be appointed as the lead chemist on the remediation programs. While not war-time in any extreme consideration, the DC sniper was active in the immediate area during 2001-2002 so added a different dimension to routine open laboratory working conditions.

    Essentially the “kill clock” model was (is?) a time-based residual chemical concentration needed in air for chlorine dioxide needed to inactivate the weapons-grade lyophilized anthrax spores found in (half a dozen?) envelopes mailed though the US Postal system. The kill clock constant needed to inactivate potential anthrax contamination was in the range of 19,000 mg/M*3/hour (milligrams/cubic meter/hour) which took some 2-3 days treatment for each. Of specific interest (and fear at the time) was that the human LD50 is only 2-3 mg/M*3. There was no other choice for gas-phase inactivation of the weaponized spores, and required intricate hydraulic diffusion throughout the completely-sealed building structures. Maintenance of the complete interior building structures at 95 degrees(F) and 98% humidity were required to aid in the inactivation process. USEPA’s Emergency Response Team complex has a versatile analytical RV unit equipped with quadrapole mass spectrometer capabilities that can detect 100 ppt (trillion) in air over one hundred miles away

    Further to the war-gas lecture equations of Col. Sawyer, those model equations also serve as part of the USEPA basis that insures public health protection through the Safe Drinking Water Act for adequate chemical and irradiation treatment of municipal drinking water. This is simply termed the CxT term (residual chemical concentration x T10, expressed in mg/L/min) constant, different for each microbial contaminant with tables developed for representative microbial contaminants. Canada recommends the same levels of disinfection treatment criteria under her Drinking Water Safety Act. Of course, municipal water treatment processes and public health are much more intricate than a few complex exponential power functions and “water chemistry”, but they are a very powerful day-to-day mainstay that trement operators and design engineers use to meet those overall public health objectives.

    As one more aside, those equations also help define models of controlling viral and bacterial inactivation by our highly-evolved biological immune systems. These are not recent concepts, having been in practive for over half a century throughout medical fields.

    Well done, Col. Sawyer. I cannot thank you enough for the motivation and guidance provided nearly half a century ago in that one single lecture. Who knew it would be so useful in providing so much fun and adventure.