Armored 
Medical Research Laboratory 
Fort Knox, Kentucky 
PROJECT NO. 3 - TOXIC GASES IN ARMORED VEHICLES 
Supplemental Report On 
Sub-Project No. 3~12 - The Carbon Monoxide Hazard from Auxiliary 
Generators in Tanks 
Project No. 3-12 
April 2, 1943 ARMORED FORCE MEDICAL RESEARCH LABORATORY 
Fort Knox, Kentucky 
Project NOo 3-12 
File No. 723.13-1 GNOML 
April 2, I9h3 
Supplemental Report On 
CARBON MONOXIDE HAZARD FROM AUXILIARY GENERATORS IN TANKS 
1° PHOJFCT: NOo 3-12, Determination of the Carbon Monoxide Hazard 
from Auxiliary Generators in Tanks« 
a° Authority - Letter Commanding General, Headquarters Armored . 
Force, Fort Knox, Kentucky, UOOoll2/6 GNOHD, dated September 2U, 
bo Purpose - To determine the magnitude of the carbon monoxide 
hazard resulting from operation of auxiliary generators in tanks when the 
tank motor is not running0 
2o DISCUSSION: 
a. Methods. This report is a supplement to the report on Ml; 
medium tanks, dated December 20, 19U2, and covers the findings on three 
additional tanks: the MUAl;, the M!?A1 vand the M7o '* 
bo Carbon monoxide concentrations were determined at three points 
inside the tank during operation of the auxiliary generator: at an opening 
in the bulkhead and at the breathing zones of the loader and driver® In 
each case the tank was located in an open yard and oriented so as to provide 
a tail windo The tank was buttoned up and the engine not running. 
£. All tests were made without modifications in the location of 
the exhaust line from the.auxiliary generator. 
. 3« CONCLUSIONS; 
. I 
a. Diffusion of carbon monoxide throughout the fighting compartment 
occurs rapidly so that the concentration in the bow is only slightly lower 
t-han in the turret. , 
bo UhAhc 
(1) Operation of the auxiliary generator in the M.J4AI4. tank when 
the tank engine is not running produces hazardous concentrations of carbon, 
monoxide in the fighting compartment. (Fig. 1)" ■ 
c. M5>A1 and M7o * . 
(1) The carbon monoxide concentrations found in the fighting 
compartments of these tanks, in the present tests, could be tolerated without 
danger for from one-half to one hour0 The data indicate that a potential 
hazard exists. (FigSo 2 and 3) kc RECOMMENDATIONS: 
a. Extend the exhaust pipe from the auxiliary generator in the 
MAM, M5A1 and M7 tanks so as to discharge beyond the rear wall of the engine 
compartment, in accordance with the recommendations of the report dated Decem- 
ber 20, 19A20 
b. Construction and maintenance of the exhaust line should be 
adequate to prevent direct leakage of exhaust gases into the fighting compart- 
ment, 
£♦ Whenever possible, the hatches should be open during operation 
of the auxiliary generator with the tank motor not running. 
Submitted by: 
Capt. Norton Nelson, 
Mr. Sgt. T. C. Swigert 
APPROVED^ 
WILLARD MACHLE 
Lt. Col,, Medical Corps, 
Commanding, 
3 Incls. 
#1 - Fig. 1 
#2 - Fig. 2 
B - Fig. 3 Fig. 
HOURS 
M4A4 
WIND 
DIRECTION 
LEGEND 
CO AT OIL RADIATOR 
CO AT LOADERS POSITION 
CO AT DRIVERS POSITION 
► AUXILIARY GENERATOR STARTED 
► HATCHES CLOSED I LEGEND 
CO AT BULKHEAD PORT 
-- CO AT LOADERS POSITION 
• _ CO AT DRIVERS POSITION 
AUXILIARY GENERATOR STARTED 
—> HATCHES CLOSED 
CARBON MONOXIDE — PERCENT 
HOURS 
Fig. 2 
M5AI 
carbon Monoxide - percent 
HOURS LEGEND 
Co AS INDICATED 
CO AT LOADER POSITION 
CO AT DRIVERS POSITION 
>> AUXILIARY GENERATOR STARTED 
► HATCHES CLOSED 
M 7 
Fig.3