The flawed toxic study was done by:
Davis Monthan AFB Bioengineering Services at the request of HQ SAC/SGPD.
Major Robert J. Sutay, Certified Industrial Hygienist, was the lead person from DM Hospital
Captain Arnold R. Ferguson, Bioenvironmental Engineer
Staff Sargent James B. Heggie, Bio Tech.
The flawed toxic study was:
Prepared by: Edward C. Bishop, Captain, USAF
Reviewed by: Arthur P. Cadwell, Col, USAF Chief, Consultant Services
Approved by: Johan E. Bayer , Colonel, USAF, Vice Commander
Misreading or not reading the unsampled work period procedure is how the Davis Monthan AFB bioengineering teams study, in 1983, miscalculated the Titan II Missile crews exposure to UDMH in the Launch Control Center (LCC) of all five missile sites tested. Seeing DM bioengineering did not sample for a total of 8 hours (in the LCC) they elected to use the wrong method to calculate the Combat Missile Crews exposure to UDMH and Hydrazine. Where did the bio-engineering team think the Titan II Missile Crew went after 262 minutes of sampling (in the LCC) so they did not get anymore exposure to the UDMH in the Launch Control Center? DM bio-engineering's assumption was the crew was no longer exposed to anything after the 262 minutes and they state it on page two of the Titan II complex report under Results and Discussion. Quoting: "The TWA CONC column is the concentration time weighted over 8 hours adjusted to 25°C, 760 mm Hg, assuming no exposure for the unsampled period." This DM AFB Titan complex study was greatly flawed. I am using the sampled UDMH measurements at the worst of the five missile sites tested which was 570-6.
a.Unsampled Work Periods. To properly calculate an employee’s TWA exposure, professional judgment is necessary to decide what assumption should be made regarding the exposure during unsampled work periods. For example, if the work shift is 8 hours and sampling was conducted for 7 hours and 15 minutes, the industrial hygienist can either assume a zero exposure for the unsampled period or assume that exposure is equal to the TWA over the sampled period. If a zero exposure is assumed for all unsampled periods, the resulting TWA is calculated per Equation 3-1a below and the industrial hygienist should document on the sampling data sheet reasons/circumstances that explain the employee's time of non-exposure (e.g., lunch break, operation completed, etc.). Where equal exposure is assumed, the resulting TWA is calculated per Equation 3-1b below and the industrial hygienist also should document the rationale on the sampling data sheet. DM AFB Bioengineering personnel failed in following this basic requirement during their testing of the Titan II Misslie Complexes!
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Equation 3-1a TWA (8-hour) = CT1+CT2+...CiTi /480 min, DM BIOENGINEERING WRONGLY USED THIS EQUATION
NOTE: Equation 3-1a, above, assumes that the average contaminant concentration during any unsampled portion(s) of the work shift is zero (0) and that the length of the work shift is 8 hours (i.e., 480 minutes). Field observations by the person conducting the sampling should determine if the zero exposure assumption is supportable. The denominator in Equation 3-1a must be the changed to the total minutes in the actual work shift if the work shift is other than 8 hours.
TWA (8-hour) = CT1+CT2+...CiTi /480 min (DM BIOENGINEERING WRONGLY USED THIS EQUATION) (103µg/m3)(262 min)/480 min=56.2µg/m3. This matches with the 570-6 DM document. Converting to parts per billion (ppb) is: (24.45 )* 56.2µg/m3 /(mole weight 60.1 of UDMH) = (24.45)(56.2)/60.1 = 23 ppb. This value matches the document column TWA CONC for the LCC.
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DM AFB BIOENGINEERING SHOULD HAVE USED THIS EQUATION TO BE CORRECT FOR JUST THE 8 HOUR TWA
Equation 3-1b TWA = CT1+CT2+CTi / T1+T2+... Ti
NOTE: Equation 3-1b, above, assumes that the contaminant concentration during any unsampled portion(s) of the work shift is equal to the average exposure for all sampled portions of the work shift. This is a conservative estimate of exposure, which is biased in favor of the worker. Field observations by the person conducting the sampling should determine if this assumption is supportable.
Where:
TWA = Time-weighted average contaminant concentration
Ci = the contaminant concentration in Sample i
Ti = the duration (minutes) of Sample i
TWA = CT1+CT2+CTi / T1+T2+... Ti (DM BIOENGINEERING SHOULD HAVE USED THIS EQUATION TO BE CORRECT FOR JUST THE 8 HOUR TWA CALCULATION) So the real TWA actual measured exposure calculation for the Combat Crew Members that stayed in the 570-6 LCC all day should have been: (103µg/m3)(262 min)/262 min = 103µg/m3 converting to ppb = (24.45)(103)/60.1 = 42 ppb TWA (8 hour only) actual calculated TWA using 262 minutes measured crew exposure at Missile site 570-6 in the LCC assuming the same exposure for the rest of the 8 hours of sample time. This is 4 times the ACGIH TWA (10ppb) that is allowed today in 2015. This still does not account for 24 hour work schedule which means to we must adjust the ACGIH allowed UDMH limit to 6.5 ppb instead of 10 ppb! So, 42 ppb UDMH TWA/6.4 ppb = 6.5. Confined to the LCC, Crew Members were exposed to six and one half times the limit allowed. See the correct method for the combat crew members.
Using Equation 3-1b and saying that the two crew members that did the Silo (out by the missile) Daily Shift Verification (DSV) for four hours and the balance of eight hours sampled in the LCC hours we can estimate the added toxic exposure to UDMH based on the DM study.
In the silo at the equipment area level six the UDMH readings were 152µg/m3 for 236 min according to DM Bioengineering.
So putting the LCC and the Silo equipment area actual readings into the equation we have: ((103µg/m3)(262 min)+(152µg/m3)(236 min) )/262 min+236 min = 26986+35872/498=126µg/m3 converting to ppb = (24.45)(126)/60.1 = 51.4 ppb TWA (8 hour only) actual calculated TWA This still does not account for 24 hour work schedule which means to we must adjust the ACGIH allowed UDMH limit to 6.5 ppb instead of 10 ppb! See the correct method to adjust the ACGIH TLV for the combat crew members. So, 51.4 ppb UDMH TWA/6.5 ppb = 8. Silo DSV Crew Members on 24 hour shift (not 48 hour alert test crews) were exposed to eight (8) times the limit allowed.
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