In this article, we investigate the use of an environmental waste (coal fly ash) in the manufacture of an ammonium nitrate corrosion resistant brick. Ammonium nitrate (AN) fertilizer spillages and vapors continuously corrode the civil structures in a fertilizer manufacturing plant situated in Zimbabwe. This situation is a safety hazard to more than a hundred plant personnel and hence a priority area for research. Our experimental results show that addition of sodium silicate improved the performance of the brick. Water absorption of bricks generally decreased with an increase in the amount of sodium silicate added. Our results also show that the compressive strength generally increased with increase in amount of sodium silicate added and that the corrosion resistance increases with the amount of sodium silicate added to the coal ash bricks.