Abstract: Flame retardant, thermoplastic molding compositions of high electroconductivity comprising between about 2% and about 45% by weight of finely divided conductive carbon black particles substantially uniformly dispersed within a cementitious matrix having a chlorine content of at least about 24% by weight and composed predominantly of substantially thermoplastic resins not substantially less than half of which by weight are vinyl chloride polymers which have a vinyl chloride content of at least about 70% by weight and K-values between about 45 and about 70, and wherein said cementitious matrix also contains from about 1% to about 15% by weight of a well balanced lubricant/stabilizer combination comprising lubricants which are solid at temperatures up to at least about 50.degree. C., together with effective stabilizers, are disclosed.