We investigate the introduction of metallic contamination from silicon carbide forks into silicon wafers during thermal annealing in a diffusion furnace. By placing one wafer on top of another on the fork, we show that the atmosphere in the furnace is not uniformly contaminated. Instead, metal evaporation from the fork (or local evaporation pressure) may be responsible for the contamination transfer. The dominant contaminants in the fork are iron, copper, and nickel, and the relation between the p-Si lifetime and the n-Si lifetime depends on these contaminants. The contamination in the fork may be due to the materials or jigs used in making it. Sodium-contamination from the fork is closely related to ambient H-2/O2 environment.