However, the Ardanans were apparently unaware that the mineral in its raw state had an undesirable byproduct: it emitted a colorless and odorless gas that temporarily impaired synaptic functions, stunting the subject's intelligence and emotional control. When the subject was removed from a high concentration of the gas, brain functions returned to normal. This medical problem was discovered by Dr. Leonard McCoy, who also learned that a simple filter mask was sufficient to prevent exposure.