Exhibit 99.1 News Release ADVANSIX ANNOUNCES FIRST QUARTER 2024 FINANCIAL RESULTS 1Q24 Sales of $337 million, down 16$0.65); Adjusted Earnings Per Share of ($0.56) 1Q24 results include approximately$27 million unfavorable pre-tax income impact from previously announced process-based operational disruption Continued commitment to corporate social responsibility and sustainability performance with ISCC PLUS certification, and EcoVadis and CDP ratings Parsippany ...