CPS Unit No. 115, subunit 30, located at the University of Illinois in Urbana, Illinois, subjected CPS men to experiments studying the effects of heat/tropical conditions.

Dr. H. H. Mitchell of the Department of Animal Husbandry directed this OSRD sponsored project studying the effect of diet under exposure to varying temperature and humidity, simulating those found in the desert and in the jungle.  Called the Heat Research Project, it was sponsored by the Animal Nutrition Laboratory at the University of Illinois and involved six to seven men at a time from September 24, 1943 to July 31, 1944.  Mennonite Central Committee provided oversight for the unit.

In the seven-man Mennonite unit, three men performed routine work in chemical analysis and calculation while the others served as subjects in a hot climate experiment.  The four spent eight hours per day in a sealed metal-lined twenty foot square chamber.  They followed various diets to discover which foods were lost most easily through sweat in high temperature and humidity. One of the subjects wrote,

The time we spend in the heat is usually more or less miserable, occasionally to the point of nausea. . .  We feel that what we are doing is of utmost importance to our country now, and later to all humanity.  It is certainly something constructive that will be of permanent value to everyone when the results are published.  We are glad that we are privileged to have a part in what is being accomplished.  (George Nachtigall, from a letter to Albert Gaeddert, March 22, 1944, in Gingerich p. 272)