Method for selective detection of liquid phase hydrocarbons

A method for selectively distinguishing the presence of the liquid phase of a hydrocarbon in an environment containing the vapor phase of said hydrocarbon, said method comprising:

• a) providing a sensor consisting essentially of a normally electrically conductive blend of a silicone polymer and a high structure carbon black of fine particle size, said carbon black being present in an amount ranging from 10-30 weight percent based on the weight of said blend;
• b) determining the electrical resistivity of said sensor when in contact with said hydrocarbon vapor phase;
• c) determining the electrical resistivity of said sensor when in contact with said hydrocarbon liquid phase;
• d) disposing said sensor in said environment in a manner which will ensure contact with any liquid phase of said hydrocarbon that may enter said environment;
• e) monitoring the electrical resistivity of said sensor;
• and
• f) signaling the presence of said hydrocarbon liquid phase when the electrical resistivity of said sensor increases to a preselected threshold level intermediate said vapor phase and liquid phase resistivities.