Class code 4635: Hydrogen or Oxygen Mfg
Class 4635 is the NCCI workers' comp code for “Hydrogen or Oxygen Mfg”.
The facts
- Official wording (NCCI)
- Hydrogen or Oxygen Mfg
- Industry group (our dictionary)
- Manufacturing—Plastics & Chemicals
- Hazard group
- G
- State codes that differ
- DE 0553 · MI 4825 · PA 0553
- Line
- Workers' comp
What it means
Class 4635 is the code carriers use to rate workers' comp payroll for this kind of work.
NCCI hazard group G, on a scale from A (least severe claims) to G (most severe).
Some states use their own code for this work: Delaware 0553, Michigan 4825, Pennsylvania 0553.
Who writes class 4635, state by state
From our live eligibility engine, refreshed every day (page updated November 1, 2026). It shows who has appetite, not a price. The final decision is always the carrier's underwriter.
Instant quote available 47
By email or underwriter only 0
No market listed yet 0
State fund only 4
North Dakota (North Dakota Workforce Safety & Insurance) · Ohio (Ohio Bureau of Workers' Compensation) · Washington (Washington Department of Labor & Industries) · Wyoming (Wyoming Department of Workforce Services)
Carriers with appetite for class 4635
- Travelers · 47 states · instant quote
- Employers · 44 states · instant quote
- CopperPoint · 19 states · instant quote
- AmTrust · 2 states · instant quote
- Markel · 2 states · instant quote
- Chubb · 47 states
- Clear Spring · 47 states
- V3- National Liability & Fire Insurance Company · 47 states
- Ascendant Commercial Insurance · 46 states
- Amerisafe · 28 states
- AIG · 7 states
- Accident Fund Insurance Company Of America · 5 states
What does class code 4635 cover?
Class 4635 is the NCCI workers' comp code for “Hydrogen or Oxygen Mfg”. Carriers use it to rate the payroll of people doing this kind of work. It sits in NCCI hazard group G.
Who writes class code 4635 workers' comp?
In our live appetite data (updated November 1, 2026), 12 carriers have appetite for class 4635 in at least one state, and 5 of them quote it instantly. An instant quote is available in 47 states. The final decision is always the carrier's underwriter.
Does every state use class code 4635?
No. In our dictionary these states use their own code for this work: Delaware 0553, Michigan 4825, Pennsylvania 0553. North Dakota, Ohio, Washington and Wyoming write workers' comp through the state fund.