It is known that plaster-of-Paris casts can cause burns. Experiments
were done to determine what factors are involved in causing an elevation of
the temperature in a freshly applied cast. A glass tube filled with water
between the temperatures of 36 and 39 degrees Celsius was used to simulate
a leg for this study. Standard plaster casts were applied to the tube and
the following variables were studied: different temperatures of the dip
water; different thicknesses of the cast; the presence of plaster residue
in the dip water; and the effect of the plaster of a pillow placed under
the tube. It was found that if the temperature of the dip water was higher
than 24 degrees Celsius or the thickness of the cast was greater than eight
ply, or both, and if the pillow was used to limit the dissipation of heat
from the cast, temperatures high enough to cause skin burns could
occasionally be reached. Variable results indicated that these were the
factors operating in practice and that a combination of them posed the
greatest hazard.