Substance use disorders are prevalent in construction workforces and often drive repeated, high-cost episodes of care. This pilot study evaluated a longitudinal, peer-delivered after-care and sobriety support program – Manifesto Health – embedded within a multi-employer union health fund covering approximately 32,000 lives in the eastern United States. A retrospective analysis of employer-paid medical, behavioral health, and pharmacy claims was conducted for all members referred to the program between the 12-month period of March 2024 and February 2025, integrating utilization data with self-report measures. Among the 152 members referred, total health-care spending averaged more than three times the plan norm ($21,380 vs. $6,900 per member per year), driven primarily by behavioral-health treatment costs that were over sixty times higher than average. Nineteen percent (n = 29) engaged at high fidelity, averaging roughly 21 sessions over six months. Twenty-one participants met criteria for longitudinal analysis. For this subgroup, annualized total costs declined from approximately $27,500 per member before engagement to $16,800 during participation which equates to a reduction of $10,800, or 37 percent. The decrease was concentrated in substance-use–related spending, with smaller reductions in mental-health care and a modest rise in general medical costs, consistent with a shift from crisis to maintenance care. Baseline self-report data confirmed elevated risks for alcohol and drug misuse, depression, and stress, aligning with the high-cost claims profile. Findings indicate that certified peer specialists can be integrated within existing employee-assistance and benefit infrastructures to provide sustained recovery support for members at elevated risk of return to use (relapse). Although promising, the results cannot establish causality due to voluntary participation, small sample size, variable observation windows, and the absence of significance testing. Moreover, claims-based analyses exclude broader returns such as employee retention and productivity, enhanced job-site safety, improved long-term stability of recovery, and reduced member cost sharing. Overall, this pilot demonstrates the feasibility and potential economic value of a peer-delivered after-care model for substance-use recovery in a labor workforce. Continued research using quasi-experimental designs, multi-year follow-up, and functional outcomes such as crisis-free and relapse-free days are warranted to estimate the full value of longitudinal peer support.