The 6H Rule at 18: Painter Certification, 98% Filters, and the Part That Went Electronic
The short version. The "6H rule" is 40 CFR part 63, subpart HHHHHH, an EPA air rule that has applied to auto body shops since 2008. It is unusual among air regulations in that almost none of it is about measuring emissions. It is about who is allowed to hold the gun, what the filter has to prove, and what you can show an inspector. That makes it checkable, which is why it is worth knowing precisely.
Read from the current CFR text on 16 August 2026. The subpart's own source credits show it was last amended on 10 November 2022.
The five requirements that carry the rule
1. An uncertified person may not spray. Not "should not". The rule says the spray application of surface coatings is prohibited by persons who are not certified as having completed the training. That is a hiring and scheduling constraint, not a paperwork one.
2. A painter's training expires. Training that meets the rule is "valid for a period not to exceed five years after the date the training is completed." A certificate with no date on it is not evidence of anything. Painters who transfer within a company into a painting role are treated as new hires.
3. The training has a required syllabus. Four topics, and an inspector can ask about any of them: spray gun selection, setup and operation, including coating viscosity, fluid tip or nozzle selection and air pressure; spray technique, including gun distance, overlap, and reducing lead and lag spraying at the start and end of each stroke; routine spray booth and filter maintenance, including filter selection and installation; and environmental compliance with this subpart. The programme must also keep a list of all current personnel by name and job description who are required to be trained.
4. Filters must be demonstrated to 98 percent. Every spray booth, preparation station and mobile enclosure must be fitted with filter technology "demonstrated to achieve at least 98 percent capture of paint overspray", by a procedure consistent with ANSI/ASHRAE Standard 52.2-2017. Note what is being demonstrated: the filter technology, not your particular booth. This is a purchasing question, and the answer should come from your filter supplier in writing.
5. Spray guns are a closed list, plus a hard door. HVLP, electrostatic application, airless, air-assisted airless, or an equivalent technology demonstrated by the manufacturer to achieve comparable transfer efficiency, and for which written approval has been obtained from the Administrator. "Equivalent" is not something a shop gets to decide for itself, and the equivalence test is a named South Coast AQMD procedure. Separately, gun cleaning must be done so that an atomized mist or spray of cleaning solvent and paint residue is not created outside a container that collects the used solvent.
Records: five years, but the first two are different
Records must be kept at least five years after the date of each record. The detail people miss is the split:
"Copies of records must be kept on site and in a printed or electronic form that is readily accessible for inspection for at least the first two years after their date, and may be kept off-site after that two year period."
So years one and two have to be reachable on site during an inspection. Years three to five may be in storage. Filing everything off-site immediately is a violation even though you kept it.
What actually changed in 2022, and what did not
This is where trade coverage most often goes wrong, so here is EPA's own description of the technology review it finalised on 10 November 2022:
"We are making no revisions to the numerical emission limits based on the technology review."
The 2022 rule did not tighten the standards. What it did was procedural, and one piece of it changes what you physically do:
Notifications go to EPA electronically. The initial notification and the notification of compliance status are submitted through the Compliance and Emissions Data Reporting Interface (CEDRI), reached through EPA's Central Data Exchange at cdx.epa.gov, uploaded as a PDF. A shop that still believes this is a letter to a regional office is working from the pre-2022 rule.
For a shop that has been open since before all this, the initial notification deadline has long passed: an existing affected source had to file no later than January 11, 2010. That is not a live deadline so much as a question you may be asked, and "we never filed one" is a different conversation from "here is the copy". A source that becomes subject later has 120 days from that point, and a new source has 180 days after initial startup.
The same action also addressed startup, shutdown and malfunction provisions, simplified the petition for exemption process, and made technical corrections.
A check worth recording: in June 2026 Congress used the Congressional Review Act to revoke a set of 2024 NESHAP amendments, and EPA amended the CFR accordingly. That revocation was to the Rubber Tire Manufacturing standards. It did not touch subpart HHHHHH. We looked, because a CRA revocation of "2024 NESHAP amendments" is exactly the kind of headline that gets misapplied to a neighbouring rule.
The methylene chloride section a newer rule has overtaken
Subpart HHHHHH contains its own methylene chloride regime for paint stripping. Management practices for everyone; and for an operation using more than one ton of MeCl a year, a written MeCl minimization plan, plus a placard or sign outlining that plan posted in each area where paint stripping occurs. Annual usage records must be on site at all times.
Read that in 2026 and notice the problem: it is a scheme for using methylene chloride carefully.
Since 29 April 2026, a different agency's rule prohibits industrial and commercial use of methylene chloride for paint and coating removal outright, under TSCA. For a collision shop, the 6H minimization plan is now a plan for something that may no longer be done at all. The prohibition, its dates, and the three carve-outs that survive are here.
Two agencies, two rules, one of them newer and stricter. When they differ, the answer is not to average them. Being in perfect compliance with the 6H methylene chloride provisions is no defence to using a chemical TSCA prohibits.
Who this does and does not cover
The exemption people reach for is for individuals working on their own things: surface coating or paint stripping performed by individuals on their personal vehicles, possessions or property, as a hobby or for maintenance. It also covers those operations performed by individuals for others without compensation.
But there is a ceiling on it, and it is specific:
"An individual who spray applies surface coating to more than two motor vehicles or pieces of mobile equipment per year is subject to the requirements in this subpart... regardless of whether compensation is received."
Two a year. Past that you are in the rule whether or not anyone paid you. This is worth knowing in both directions: it is not a doorway for a commercial shop, and it is a real limit on the hobbyist who has started doing favours.
Enforcement may not be EPA. The subpart can be implemented and enforced by EPA or by a delegated State, local or tribal agency. One authority is expressly retained by the Administrator and not delegated: the equivalent-spray-gun approval at § 63.11173(e)(5). So the one determination a shop might most want a friendly local answer on is the one only Washington can give.
How this was checked
The rule was read from the current text of 40 CFR part 63, subpart HHHHHH, retrieved on 16 August 2026 from eCFR's published API at title 40's most recent issue date of 13 August 2026. Every quotation and figure above is from that text. Its source credits record the subpart as promulgated at 73 FR 1759 on 9 January 2008 and amended at 85 FR 73920 in November 2020 and 87 FR 67804 and 67805 on 10 November 2022.
The characterisation of the 2022 technology review comes from the Federal Register's own record for document 2022-24129. The Congressional Review Act check used the Federal Register record for document 2026-12424.
eCFR and FederalRegister.gov return a bot-check page to automated requests for their website pages, and that page states programmatic access is via their developer APIs. We used the APIs, which is the route the operators designate, and did not retry the website pages.
One figure this page does not give you: whether your state has been delegated enforcement. That varies, it changes, and the rule itself tells you to ask your EPA Regional Office rather than guess.
- The methylene chloride paint stripper prohibition
- What Federal OSHA actually cites in body shops
- Refinish materials and paint procedures
General consumer information: not legal, insurance, or financial advice. Requirements, coverage, and practices vary by state, policy, and manufacturer.
Where this fits
Each link says what it is for. We add one only when a reader on this page has a real reason to need that page next.
- Half a Pint an Hour: The Texas Threshold That Decides Whether Your Shop Registers (the state air authorisation a Texas shop needs on top of this, and the threshold that decides which)
- Medical Evaluation Comes Before the Fit Test. That Order Is the Whole Rule. (the most-cited standard in body shops, and the order its steps have to happen in)
- 217 Citations, 53 Inspections: What Federal OSHA Actually Wrote Up in Body Shops (what inspectors actually write up, which is not what most shops prepare for)
- What EPA's Compliance Database Actually Says About Body Shops (what the federal enforcement record actually shows for shops under this rule, and why seven in ten rows record no inspection at all)