{"data":{"id":"us/40-cfr-1039.520","jurisdiction":"us","citation":"40 CFR 1039.520","heading":"What testing must I perform to establish deterioration factors?","body":"Sections 1039.240 and 1039.245 describe the method for testing that must be performed to establish deterioration factors for an engine family.","path":["Title 40—Protection of Environment","CHAPTER I—ENVIRONMENTAL PROTECTION AGENCY","SUBCHAPTER U—AIR POLLUTION CONTROLS","PART 1039—CONTROL OF EMISSIONS FROM NEW AND IN-USE NONROAD COMPRESSION-IGNITION ENGINES","Subpart F—Test Procedures"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-40.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:26:04Z","sha256":"38a6498d0f531c37bb4a77ea17c2e289f70aff7f76762ea2cb80dc26df428f33","source_id":"us-cfr","stale":true,"prev":"us/40-cfr-1039.515","next":"us/40-cfr-1039.525"},"notice":"GroundRules: Original legal text. Not legal advice."}