Abstract: An environmental shield for reducing or eliminating leakage of materials from transit vehicles, including truck-mounted concrete mixers, is provided. The environmental shield preferably engages at least a portion of an opening on a mixer drum such that the leakage that generally occurs in such situations as travel along hilly or bumpy terrain, surging, etc. may be prevented or minimized. The environmental shield preferably includes a discharge cover and a combination steel/rubber abrasion resistant sealing member and may be preferably coupled to a charging hopper of the transit vehicle.