sˌʌm ʌvðə ɹˈɛɡjʊlɚ kəntɹˈɪbjuːɾɚz tʊ ˈɪmpækt ɪŋklˈuːdᵻd ˈænɪməl ɹˈaɪts ˈædvəkˌeɪt ænd ˈɔːθɚ stˈiːvən bˈɛst, sˈoʊʃəl ænd pəlˈɪɾɪkəl ˈæktɪvˌɪst pˈɔːl ɹˈɑːɡæt lˈoʊb, kɑːɹtˈuːnɪsts kˈiːθ nˈaɪt ænd stˈɛfəni mək mˈɪlən, ænd mˈɔːɹɪs sˈʌlɪvən, æz wˈɛl æz kˈɑːləmnˌɪsts ˈædəm fˈɪnli, pˈætɹɪk skˈɑːt bˈɑːɹnz, dˈɑːn pˈiːflˈæstɚ, ænd ˈʌðɚz.
Some of the regular contributors to IMPACT included animal rights advocate and author Steven Best, social and political activist Paul Rogat Loeb, cartoonists Keith Knight and Stephanie McMillan, and Morris Sullivan, as well as columnists Adam Finley, Patrick Scott Barnes, Don Pflaster, and others.