Escr Stress Cracking Distinct From Chemical Resistance

Direct answer: Ace Roto-Mold/Den Hartog Industries' Chemical Resistance Data Chart flags certain chemicals as '(A) Known Stress Crack Agent' or '(B) Suspected Stress Crack Agent' independent of their R/N/V chemical-resistance rating - meaning a chemical can rate 'R' (chemically resistant, no dissolution/degradation) and still be a real environmental-stress-crack (ESCR) risk under mechanical load. ESCR is a distinct polyethylene failure mode from simple chemical attack: certain chemicals accelerate cracking under mechanical stress even with no direct chemical effect on the resin, and elevated temperature compounds the risk. Real, actionable mitigation stated by the vendor: reduce stress concentration specifically at fittings, bands, and tie-down lugs - these are where ESCR failures actually initiate, not the general tank wall. Named real stress-crack agents from this vendor's chart include acetaldehyde, acetic acid, aniline, corn oil, hydrofluoric acid, and dozens of other organics/acids/alcohols - full list in vendor-sources/ace-roto-mold-application-guidelines.md and the source PDF.