The effects of lead, bismuth, silver, and selenium additions (at three levels each) on the workability and mechanical properties of Unitemp 718 are reported. Findings of this study include: (i) no significant effects on room temperature or 1200 °F tensile or yield strength were observed; (ii) 1200 °F stress rupture lives, and stress rupture and tensile ductilities decreased sharply with increasing content of all four trace elements: (iii) only selenium additions had a detrimental effect on workability. The lack of correlation of analytical data among laboratories noted in this study underscores the need to improve the reliability and reproducibility of analytical data through the establishment of standards for trace elements analyses.