(A) Comminuted (less than or equal to1.6 mm) spent-tire rubber scrap (0.25-0.75 mm, 87%; Cd, Hg, As less than or equal to 0.00025%, Sb, Pb, Ba less than or equal to 0.002%); (B) heat-pretreated (20-90 min, 150degreesC) phosphogypsum (60 pm; Cd, Hg, As less than or equal to 0.0001%, Sb, Pb, Cr less than or equal to 0.001%, Ba less than or equal to 0.01%); and (C) polyester-glass fiber laminate extracted (> 1 atm) with CH2Cl2 to yield 67% glass fibrous products (contain 70 wt.% glass fiber) and 30% resin powder (contain 3.5% glass fiber), were used to fill LDPE, PP. polyamide 6 (PA 6), and diisooctyl phthalate-plasticized PVC, compositions. LDPE, PP and PA6 were granulated with A, B or C in a single- or twin-screw extruder and PVC was dry-blended with A or B. Mechanical properties (Shore hardness, Taber abrasion, indentation, etc.), thermal stability, and MFR of the A, B or C-filled LDPE, PP and PA 6 were as good as or better than those of conventional mineral-filled compositions. Each composition tent itself to making utility (agri, horti, automotive, household, road safety, etc.) equipment. The A or B-filled LDPE, PP or PVC can also be recycled to make large-size road safety equipment which, after use, can be incinerated. 18 refs.