Abstract: A polymer composition has a filler of particulate conductive material including at least 0.5% by weight of char carbon produced by carbonization of plant material, particularly herbaceous straw. The filler may also contain other conductive materials such as carbon black. Compositions with electrical resistivities over a wide range may be produced, preferably with polymers adapted for use as coatings. In particular compositions with surface resistivities between 10.sup.6 and 10.sup.9 ohms per square are available and find use as antistatic coatings, avoiding the excessively rapid discharge of static electricity that occurs with fillers of carbon black alone.