Exhibit 99.1 1Q26 Sales of $404 million, up 7% versus prior year 1Q26 Earnings Per Share of ($0.58); Adjusted Earnings Per Share of ($0.50) 1Q26 Cash Flow from Operations of ($15) million News Release ADVANSIX ANNOUNCES FIRST QUARTER 2026 FINANCIAL RESULTS Evaluating Expansion of Integrated Ammonia Platform to Meet Growing Regional Demand for Diesel Exhaust Fluid (DEF) Appointed Patrick Day as SVP and CFO, effective April 27th Parsippany, N.J., May 8, 2026 - AdvanSix (NYSE: ASIX), a vertically integrated ch ...