nor education 9 min read

By TerraCare

How Does Natural Organic Reduction Work? The Microbial Science Explained (colloquially referred to as human composting)

Natural organic reduction (NOR) works by placing the body in a vessel with organic materials — primarily wood chips and straw — and allowing naturally occurring microorganisms to break down the remains through a controlled, heat-driven biological process. Temperature, moisture, and oxygen are carefully managed throughout. The result, after several weeks to a few months, is approximately one-half cubic yard of nutrient-rich soil that can be returned to the family and used to nourish living ecosystems.

If you’ve heard of terramation and want to understand what’s actually happening on a biological level, this article walks through the science in plain terms — no microbiology degree required. For a broader overview, see our complete guide to natural organic reduction.

How does natural organic reduction (terramation) work?

Natural organic reduction places the body in a vessel with wood chips, straw, and other organic material. Naturally occurring microorganisms break the remains down through aerobic microbial decomposition, generating heat above 131°F that eliminates pathogens. After several weeks to a few months, the process yields approximately one-half cubic yard of nutrient-rich soil.

  • NOR uses aerobic microbial decomposition — the same biology as industrial composting — to break human remains into soil over several weeks to a few months.
  • Wood chips provide carbon and aeration structure; straw regulates moisture — together they create the optimal 25:1–30:1 carbon-to-nitrogen ratio for efficient decomposition.
  • Thermophilic bacteria generate internal vessel temperatures of 131–160°F, which simultaneously accelerates decomposition and destroys pathogens.
  • Fungi break down lignin in wood chips, unlocking carbon that bacteria cannot access on their own.
  • The finished product — approximately one-half cubic yard of Regenerative Living Soil™ — is nutrient-dense, screened, and safe for use in gardens or conservation projects.
  • NOR is a regulated, facility-based process with documented chain of custody, distinguishing it sharply from uncontrolled outdoor decomposition or backyard composting.

What Happens Inside the Vessel During Natural Organic Reduction?

The process begins when the body is placed inside a specialized vessel — at TerraCare Partners, this is the Chrysalis™ — along with a carefully calibrated mix of wood chips, straw, and other organic plant material. These aren’t random yard waste. Each material serves a specific biological function.

Wood chips provide carbon, the primary energy source for microorganisms. They also create physical structure — air pockets that allow oxygen to circulate throughout the vessel. Straw adds more carbon and helps regulate moisture. Together, these materials create what microbiologists call a favorable carbon-to-nitrogen ratio — the balance that sustains rapid, thorough decomposition.

Once the vessel is sealed, microbial activity begins almost immediately. Bacteria and fungi — naturally present in the environment and already living on and inside the human body — begin consuming the organic material. As they metabolize it, they generate heat. This self-generated heat distinguishes NOR from slower, passive decomposition.

The vessel environment is actively monitored. Oxygen is supplied to sustain aerobic microbial activity, which is faster and more thorough than anaerobic decomposition. Moisture is maintained within a target range — too dry and activity stalls; too wet and the process becomes anaerobic and inefficient.

What Role Do Microorganisms Play in the NOR Process?

Microorganisms are not just participants in natural organic reduction — they are the engine of the entire process.

Bacteria do the heavy lifting in the early and peak-heat phases. Certain bacterial species are specifically adapted to high-temperature environments, collectively called thermophilic bacteria. As the temperature inside the vessel climbs, these heat-tolerant organisms become dominant and dramatically accelerate decomposition. They produce enzymes that break down proteins, fats, and complex organic molecules into simpler compounds.

Fungi contribute differently. Where bacteria break down softer organic material quickly, fungi are particularly effective at digesting lignin — the tough structural compound in wood. This is why wood chips are a critical ingredient rather than an afterthought: they provide the substrate that fungal communities thrive on, which in turn helps break down the more resistant components of human tissue and bone over time.

The microorganisms are not introduced by the facility. They are naturally present in the organic materials and within the human body itself. The facility’s role is to create the right conditions — carbon-to-nitrogen ratio, moisture, oxygen — so these communities can work efficiently.

For a deeper look at the specific microbial communities involved in terramation, see our article on microorganisms in the terramation process.

How Is Temperature Controlled — and Why Does It Matter?

Temperature is arguably the most important variable in natural organic reduction, for two reasons: it drives decomposition speed, and it determines pathogen elimination.

As microbial communities metabolize organic material, they generate heat. In a well-managed vessel, internal temperatures routinely reach thermophilic levels — 131°F (55°C) or higher — sustained over a period of days. This is not external heating applied from the outside; it is biological heat generated by the organisms themselves.

This matters enormously for safety. Sustained thermophilic temperatures are lethal to most human pathogens, including bacteria, viruses, and parasites. Regulatory requirements in states where NOR is legal specify minimum time-temperature thresholds that must be maintained and documented — similar to the standards used in industrial composting for biosolids. The vessel environment is monitored throughout, and the process typically includes rotation or aeration steps to ensure uniform heat distribution across the entire vessel contents.

The thermophilic phase does not last forever. As the available organic material is consumed, microbial activity naturally slows, temperatures drop, and the process enters a curing or maturation phase. This is where the material stabilizes into what will become the finished soil product.

How Is NOR Different From Backyard Composting?

This comparison comes up often, and it’s worth addressing directly: natural organic reduction is not composting in the way most people understand the word.

Home composting is informal and uncontrolled. You pile organic matter, wait, turn it occasionally, and get results that vary widely. There is no regulatory framework, no identity tracking, no documented temperature logs, and no consistent outcome.

NOR is a regulated, facility-based process with documented protocols maintained under state oversight. Every vessel is tracked throughout to ensure chain of custody — meaning the soil returned to a family comes from their loved one, not a commingled batch. The process is designed to be reproducible and verifiable.

The biological mechanisms share common ground, but the similarity ends there. NOR operates at a level of precision and accountability that makes the “backyard composting” comparison misleading.

For a full breakdown of these distinctions, see how terramation is different from composting.

Learn more about terramation providers near you

What Does the Soil Look Like When the Process Is Complete?

When the thermophilic and curing phases are complete, the material is removed from the vessel and screened to remove any remaining bone fragments, which are then processed separately and reintegrated into the final product. What remains is a dark, earthy-smelling soil material that is visually indistinguishable from high-quality garden compost.

At TerraCare Partners, this finished material is called Regenerative Living Soil™. It is nutrient-dense, microbially active, and structurally similar to the rich organic matter found in healthy forest floors. Families receive approximately one-half cubic yard of finished soil — which can be used in gardens, spread across land, used in conservation restoration projects, or retained as a living memorial.

The soil contains no preservatives, no formaldehyde, and no cremation-related emissions. It is the biological end product of a process that returns the human body to the nutrient cycle in the most direct way available.

How Long Does Natural Organic Reduction Take?

The duration varies depending on the system, vessel conditions, and the individual. As a general range, the process takes several weeks to a few months from placement to return of finished soil.

This timeline spans all phases: initial microbial activation, the thermophilic peak, curing and maturation, and final screening and processing. Facilities may approach each phase differently, which accounts for variation between providers.

NOR takes longer than cremation, which runs a few hours. That additional time reflects the difference between a chemical combustion process and a biological one — and produces a fundamentally different outcome.

Is natural organic reduction safe?

Yes. NOR is a regulated process that operates under state law and is subject to facility oversight. The thermophilic temperatures reached during processing are sufficient to eliminate pathogens, and facilities maintain documented temperature logs to verify compliance. The finished soil product meets or exceeds safety standards for use in landscaping and gardens.

Does NOR eliminate pathogens?

Yes. Sustained temperatures of 131°F (55°C) or higher — maintained for the required duration — are lethal to the vast majority of human pathogens, including common bacteria, viruses, and parasites. This is the same principle used in regulated industrial composting for biosolids. Facilities are required to demonstrate that these thresholds have been met before the soil is returned to the family.

Can any body be processed through NOR?

Most individuals can be processed through NOR. Facilities typically have weight and size guidelines, and certain implants (such as radioactive medical devices) may need to be removed in advance, consistent with requirements that also apply to cremation. The facility will review individual circumstances during arrangement discussions. Embalming is generally not used prior to NOR, as embalming chemicals interfere with the natural microbial process.

Is the soil from NOR safe to use in a garden?

Yes. Regenerative Living Soil™ is a biologically active, nutrient-rich soil amendment that is safe for use in gardens, on land, or in conservation planting. It does not contain pharmaceutical residues at levels that pose a concern for typical use. Families receive guidance on appropriate applications at the time of delivery.

Natural organic reduction is currently legal in 14 states: Washington, Colorado, Oregon, Vermont, California, New York, Nevada, Arizona, Maryland, Delaware, Minnesota, Maine, Georgia, and New Jersey. Note that California, New York, and New Jersey have passed legislation but are not yet fully operational. For a complete state-by-state breakdown, visit our guide to states where NOR is legal.

Ready to explore terramation options? Contact TerraCare Partners

Sources

  1. Washington State Legislature — WAC 246-500: Natural Organic Reduction. https://app.leg.wa.gov/wac/default.aspx?cite=246-500
  2. Washington State University Extension — Research on Terramation / Natural Organic Reduction. https://extension.wsu.edu
  3. Washington State Department of Ecology — Homepage. https://ecology.wa.gov/
  4. National Funeral Directors Association (NFDA) — Cremation and Burial Report: Statistics and Trends. https://www.nfda.org/news/statistics
  5. Washington State University Extension — Natural Organic Reduction of Human Remains: A Review of the Science. WSU Extension Publication, 2019. https://extension.wsu.edu
  6. U.S. Environmental Protection Agency — Standards for the Use or Disposal of Sewage Sludge (40 CFR Part 503): Pathogen Reduction Requirements. https://www.epa.gov/biosolids/biosolids-laws-and-regulations
  7. Colorado Revised Statutes § 25-13-101 et seq. — Natural Reduction of Human Remains Act (SB 21-006). https://leg.colorado.gov/bills/sb21-006
  8. Oregon Revised Statutes § 97.721 et seq. — Natural Organic Reduction: Disposition of Human Remains. https://www.oregonlegislature.gov/bills_laws/ors/ors097.html
  9. Roach, M. (2003). Stiff: The Curious Lives of Human Cadavers. W.W. Norton. [Background on decomposition biology and historical context.]
  10. Rynk, R., et al. (2022). The Composting Handbook: A Practical Guide to Making and Using Compost. Academic Press. [Reference for carbon-to-nitrogen ratio fundamentals in aerobic decomposition.]