# ChesHaz — Quick chemical hazmat id

> Offline chemical hazmat identification by UN/NA placard number. (iPhone/iPad app by WIlliam Cheswick.)

- Source: https://appshunter.io/ios/app/cheshaz/id1320963064 (this page in markdown: same URL + `.md`)
- Developer: [WIlliam Cheswick](https://appshunter.io/developer/419708950)
- Category: Reference, Education
- Price: Free
- Rating: 5.00/5 from 4 App Store ratings · 2 written reviews indexed
- Age rating: 4+
- Requires: iOS 10.0 · 3 MB
- Languages: American English
- Released: 2017-12-16
- Data updated: 2026-06-01
- Monetization: free
- User reviews in markdown: https://appshunter.io/ios/app/cheshaz/id1320963064/reviews.md

## What is ChesHaz?

This is a quick, free app to look up the four-digit "UN/NA" numbers on the hazmat placards affixed to highway and rail tankers.  The chemical names and other information is shown.

The main data is stored off-line, so it is available when there is no network connectivity.  There are links to Wikipedia pages and official online information from NOAA in the US.

This app was written for educational purposes only. Though this data is carefully derived from official US government web pages and is believed to be presented accurately, first responders and other life savers should probably rely on hazmat apps from official sources.

## Key features

- Offline UN/NA number lookup
- Chemical name display
- Links to Wikipedia
- Links to NOAA information
- Educational purposes

## Recent user reviews (2 of 2)

All indexed reviews: https://appshunter.io/ios/app/cheshaz/id1320963064/reviews.md

### 5/5 — Sweet single-purpose app

*2019-01-31*

This app is designed to do one thing (identify 'hazmat' diamond placards), and it does that one thing very well.

### 5/5 — Very Handy Reference

*2017-12-17*

This is a great app for emergency responders that don’t have there reference guidebook to understand what hazard they may be approaching at a scene or for the curious passenger wondering what’s in the truck your stuck behind on traffic.  

Best of all you can link to reference material on line if you need details for a response.

## Frequently asked questions about ChesHaz

### What is ChesHaz?

ChesHaz is a free reference app designed for quickly looking up four-digit UN/NA numbers found on hazmat placards. It displays chemical names and provides links to external resources for more information.

### Does ChesHaz work offline?

Yes, the main data for ChesHaz is stored offline, allowing you to access information even without a network connection.

### Is ChesHaz suitable for professional first responders?

The app is intended for educational purposes. While derived from official sources, first responders are advised to rely on hazmat apps from official sources for critical situations.

### What devices support ChesHaz?

ChesHaz is supported on iPhone, iPad, and iPod devices.

### How often is ChesHaz updated?

The latest version, 2.1, was released on December 5, 2018. The app was initially released on December 16, 2017.

### What is the age rating for ChesHaz?

ChesHaz has an age rating of 4+.

### Does ChesHaz contain advertisements?

No, ChesHaz does not contain advertisements.

### What is the user rating for ChesHaz?

ChesHaz has a high rating of 5.0 stars based on 4 user ratings.

## Version history (last 5 releases)

### 2.1 — 2018-12-05

Jayla's mod: clear the screen when the UN/NA number is invalid.

### 2.0 — 2018-11-02

A UN/NA number is sometimes a class of transported substances.  When available the app now lists some of the chemicals in the class.

### 1.9 — 2018-09-18

Fixed some keyboard input bugs, and updated the databases.  Preparing for a Siri interface.

### 1.4 — 2018-02-28

This app now uses a custom numeric keypad which shows only the digits with available information.  The new keypad moves out of the way and may be restored by tapping the numbers field.

ChesHaz now keeps a list of your substance queries in the app, which may be reviewed, edited, emailed, or cleared.

Some layout issues and bugs were fixed.

### 1.1 — 2018-02-10

Layout bug fixes and iPhone X support.  

More information displayed, and clear links to external official web pages.

## Apps similar to ChesHaz

| App | Rating | Price | Category |
| --- | --- | --- | --- |
| [CAMEO Chemicals](https://appshunter.io/ios/app/cameo-chemicals/id1151912682) | 4.2 (25) | Free | Reference |
| [UN Numbers Dangerous Goods ADR](https://appshunter.io/ios/app/un-numbers-dangerous-goods-adr/id1668677326) | — | Free | Reference |
| [Hazmat Registration Search](https://appshunter.io/ios/app/hazmat-registration-search/id1459678141) | 5.0 (2) | Free | Reference |
| [UN Number](https://appshunter.io/ios/app/un-number/id307373793) | 4.7 (49) | Free | Reference |
| [HazMat Reference](https://appshunter.io/ios/app/hazmat-reference/id385775821) | 4.8 (1,590) | $4.99 | Reference |
| [DOT Chart 17](https://appshunter.io/ios/app/dot-chart-17/id1245251292) | 2.3 (3) | Free | Reference |

## More apps by WIlliam Cheswick

- [iTeX](https://appshunter.io/ios/app/itex/id419708947)

All apps by WIlliam Cheswick: https://appshunter.io/developer/419708950

## Related topics

[hazardous materials](https://appshunter.io/ios/topics/hazardous-materials) · [hazmat reference](https://appshunter.io/ios/topics/hazmat-reference)

---

*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-06-01.*