This question will be addressed in a later section after the various studies are described. A double-blind analysis of various unused, helium implanted, and electrolyzed palladium was done early in the field's history. This amount is too small to account for the heat by a factor of 36. A clear conclusion is compromised because the as-received palladium contained much more helium than normally seen in such material, making the nature of the electrolyzed sample uncertain. For these reasons, the work was generally rejected.
Subsequent studies are more convincing.
The first measurement of helium in the evolved gas was provided by Miles et al. Eight gas samples taken in Pyrex flasks during heat production contained helium while six control cells showed no helium above background. Because glass was used to contain the gas, the results might have resulted from diffusion of helium through the glass. In response to these concerns, the investigators measured the diffusion rate of helium through glass, When corrections were made, excess helium remained in the flasks. These results are shown in Figure 6.