# Toxic: Building Code Definition

> How the IBC 2009, IFC 2009 define toxic, where the wording differs, and which chapters depend on the term.

- Canonical: https://harth.build/resources/glossary/toxic/
- Last updated: 2026-09-07
- Data source: Definitions quoted from the 2009 International Codes as transcribed in this site's building-codes collection, with the source chapter linked for each quotation. Usage counts are computed over the chapters hosted here, one copy per code. The [ICC code library](https://codes.iccsafe.org/codes) publishes the current model text and the [ICC adoption maps](https://www.iccsafe.org/advocacy/code-adoption-maps/) show which edition a jurisdiction has adopted; those sources control.

## Key facts

| Fact | Value |
| --- | --- |
| Defined in | IBC 2009, IFC 2009 (2009 editions transcribed in this corpus) |
| Primary source | IBC 2009 Use and Occupancy Classification (model text, not a jurisdiction's adopted text) |
| Chapters using the term | 30 (counted across the codes hosted here) |
| Wording identical across codes | Yes (compare before citing one code's wording under another) |

## Direct answer

Toxic is a defined term in the International Building Code (IBC) 2009, in Use and Occupancy Classification. The code's own words are: “A chemical falling within any of the following categories:” The IFC 2009 carries the same definition word for word, so the term means the same thing in each. The term is used in 30 chapters of this corpus, most often in Highly Toxic and Toxic Materials (IFC 2009), Exhaust Systems (IMC 2009), Hazardous Materials-general Provisions (IFC 2009). These pages transcribe the 2009 model text; verify the definition against the edition and amendments your authority having jurisdiction has adopted. Record the jurisdiction, the adopted edition, the application date and any local amendment that rewrites the definition before you use it on a live project, because a term redefined by amendment changes every requirement that depends on it.

*Content and cited inputs reviewed by [Scott Barrington](https://nz.linkedin.com/in/barrington), Harth founder and architectural technology specialist · Published 2026-09-07 · Updated 2026-09-07.*

## What does this term mean?

**Toxic** — IBC 2009, Use and Occupancy Classification:

> A chemical falling within any of the following categories:

![Labeled code-term definition diagram: Toxic: Building Code Definition](https://efwwel0vyt9vy5so.public.blob.vercel-storage.com/images/glossary/toxic/diagram-1344.webp)

*How the IBC 2009, IFC 2009 define toxic, where the wording differs, and which chapters depend on the term.*

## What must be verified before using this guidance?

Two of the I-Codes in this corpus define **Toxic**, in identical words.

| Code | Where it is defined | Definition |
| --- | --- | --- |
| IBC 2009 | [Use and Occupancy Classification](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/use-and-occupancy-classification.md) | A chemical falling within any of the following categories: |
| IFC 2009 | [Highly Toxic and Toxic Materials](https://harth.build/resources/building-codes/us-states/rhode-island/ifc-2009/highly-toxic-and-toxic-materials.md) | A chemical falling within any of the following categories: |

## Where toxic is used in the code

The term appears in 30 chapters of the 2009 I-Codes hosted here. The chapters that lean on it hardest are the ones to read next.

| Chapter | Code | Mentions |
| --- | --- | --- |
| [Highly Toxic and Toxic Materials](https://harth.build/resources/building-codes/us-states/rhode-island/ifc-2009/highly-toxic-and-toxic-materials.md) | IFC 2009 | 277 |
| [Exhaust Systems](https://harth.build/resources/building-codes/us-states/new-hampshire/imc-2009/exhaust-systems.md) | IMC 2009 | 107 |
| [Hazardous Materials-general Provisions](https://harth.build/resources/building-codes/us-states/rhode-island/ifc-2009/hazardous-materials-general-provisions.md) | IFC 2009 | 56 |
| [Semiconductor Fabrication Facilities](https://harth.build/resources/building-codes/us-states/rhode-island/ifc-2009/semiconductor-fabrication-facilities.md) | IFC 2009 | 42 |
| [Special Detailed Requirements Based on Use and Occupancy](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/special-detailed-requirements-based-on-use-and-occupancy.md) | IBC 2009 | 25 |
| [Building Services and Systems](https://harth.build/resources/building-codes/us-states/rhode-island/ifc-2009/building-services-and-systems.md) | IFC 2009 | 22 |
| [Fire Protection Systems](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/fire-protection-systems.md) | IBC 2009 | 20 |
| [Definitions](https://harth.build/resources/building-codes/us-states/new-hampshire/imc-2009/definitions.md) | IMC 2009 | 18 |
| [Use and Occupancy Classification](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/use-and-occupancy-classification.md) | IBC 2009 | 12 |
| [Electrical](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/electrical.md) | IBC 2009 | 8 |
| [Means of Egress](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/means-of-egress.md) | IBC 2009 | 8 |
| [Definitions](https://harth.build/resources/building-codes/us-states/rhode-island/ifc-2009/definitions.md) | IFC 2009 | 8 |

_18 further chapters mention the term._

### The term in use

How the code actually writes about toxic, quoted from the 2009 text hosted here:

> The storage and use of highly toxic and toxic materials shall comply with this chapter.

— [IFC 2009 §3701.1](https://harth.build/resources/building-codes/us-states/rhode-island/ifc-2009/highly-toxic-and-toxic-materials.md)

> Hazardous emissions include flammable vapors, gases, fumes, mists or dusts, and volatile or airborne materials posing a health hazard, such as toxic or corrosive materials.

— [IMC 2009 §510.1](https://harth.build/resources/building-codes/us-states/new-hampshire/imc-2009/exhaust-systems.md)

> Highly toxic and toxic gases shall also comply with Section 3704.2.2.6.

— [IFC 2009 §2703.8.4.2](https://harth.build/resources/building-codes/us-states/rhode-island/ifc-2009/hazardous-materials-general-provisions.md)


## The terms toxic is built out of

The definition above leans on 1 other defined term. Each carries its own code definition, and a local amendment to any of them changes what toxic covers:

- **[Chemical](https://harth.build/resources/glossary/chemical.md)** — IFC 2009: An element, chemical compound or mixture of elements or compounds or both.

## Toxic: what to open, and in what order

Every row is a document this term depends on. The [ICC code library](https://codes.iccsafe.org/codes) and the [ICC adoption maps](https://www.iccsafe.org/advocacy/code-adoption-maps/) cover the middle rows.

| Check | Where | Confirmed |
| --- | --- | --- |
| Read the definition in the adopted IBC | Use and Occupancy Classification | |
| Read the definition in the adopted IFC | Highly Toxic and Toxic Materials | |
| Re-check the requirement that uses it | Highly Toxic and Toxic Materials (IFC 2009) | |
| Re-check the requirement that uses it | Exhaust Systems (IMC 2009) | |
| Re-check the requirement that uses it | Hazardous Materials-general Provisions (IFC 2009) | |
| Re-check the requirement that uses it | Semiconductor Fabrication Facilities (IFC 2009) | |
| Confirm the dependent definition | Chemical | |
| Local amendment to any of the above | Jurisdiction's amendment list | |

**A research aid, not a code determination.** The authority having jurisdiction decides which edition and which amendments apply.

## Where can you explore related guidance?

- [Explore all glossary guidance](https://harth.build/resources/glossary.md)
- [Chemical: Building Code Definition](https://harth.build/resources/glossary/chemical.md)
- [Corrosive: Building Code Definition](https://harth.build/resources/glossary/corrosive.md)
- [Hazardous Materials: Building Code Definition](https://harth.build/resources/glossary/hazardous-materials.md)
- [Combustible Liquid: Building Code Definition](https://harth.build/resources/glossary/combustible-liquid.md)

## Sources and method

Definitions quoted from the 2009 International Codes as transcribed in this site's building-codes collection, with the source chapter linked for each quotation. Usage counts are computed over the chapters hosted here, one copy per code. The [ICC code library](https://codes.iccsafe.org/codes) publishes the current model text and the [ICC adoption maps](https://www.iccsafe.org/advocacy/code-adoption-maps/) show which edition a jurisdiction has adopted; those sources control.

### Source links

- [codes.iccsafe.org](https://codes.iccsafe.org/codes)

- [iccsafe.org](https://www.iccsafe.org/advocacy/code-adoption-maps/)

## Frequently asked questions

### What is the code definition of toxic?

The International Building Code (IBC) 2009 defines it in Use and Occupancy Classification as: “A chemical falling within any of the following categories:” The 2009 model text is reproduced here; the definition that binds your project is the one in the edition your jurisdiction has adopted, as amended locally.

### Which parts of the code depend on toxic?

In this corpus the term is used across 30 chapters, led by Highly Toxic and Toxic Materials in the IFC 2009. Those are the sections whose scope moves if the definition is amended locally, so read them together with Chapter 2 rather than on their own.

### What does IBC mean in building codes?

Building is a separate defined term. The IBC 2009 defines it as: “Any structure used or intended for supporting or sheltering any use or occupancy.” That is not the same as toxic, which the IBC 2009 defines as “A chemical falling within any of the following categories:” — read both before applying either, and confirm the wording in the edition your jurisdiction has adopted.

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