ALOHA Software

Three-colored threat zone estimate for a fictional chlorine release, as shown on an ALOHA grid.

ALOHA is the hazard modeling program for the CAMEO software suite, which is used widely to plan for and respond to chemical emergencies.  Learn more about the CAMEO software suite.

ALOHA allows you to enter details about a real or potential chemical release, and then it will generate threat zone estimates for various types of hazards.  ALOHA can model toxic gas clouds, flammable gas clouds, BLEVEs (Boiling Liquid Expanding Vapor Explosions), jet fires, pool fires, and vapor cloud explosions.  The threat zone estimates are shown on a grid in ALOHA, and they can also be plotted on maps in MARPLOT, Esri's ArcMap, Google Earth, and Google Maps.  The red threat zone represents the worst hazard level, and the orange and yellow threat zones represent areas of decreasing hazard.

Downloading ALOHA

The Windows version can be run on Windows 7, 8, and 8.1 operating systems. The Macintosh version can be run on Mountain Lion (10.8.x), Mavericks (10.9.x), and Yosemite (10.10.x) operating systems. Operating systems not listed here have not been tested and are not supported.

If you already have an older version of ALOHA: It is best to install the new ALOHA application in the same folder as your previous version. This will replace the old application with the new one, while still maintaining all of your settings. Any chemical information that you have added to the chemical library will not be saved and you will need to re-enter that information.

Learning More About ALOHA

For a brief summary of the ALOHA program and its capabilities, download the ALOHA fact sheet (PDF).(2pp, 601 KB, About PDF)

ALOHA's help topics include an example problem that you can work through to familiarize yourself with the program.  You can also download the ALOHA Examples (PDF), which has three additional step-by-step fictional example scenarios.(53pp, 2 MB, About PDF)

For additional information on using ALOHA (such as FAQs, a Level of Concern guide, tools for importing threat zones into Esri's ArcGIS products, and the Ask. Dr. ALOHA articles), see the ALOHA pages on the NOAA Office of Response and Restoration site.

For information about ALOHA's models and equations, as well as other background information, download the ALOHA Technical Documentation (PDF).(96 pp, 1.3 MB, About PDF)

What's New in ALOHA Version 5.4.5?

  • Updated chemical library, including new DIPPR chemical data and new Levels of Concern (AEGLs and ERPGs).
  • Added new RAILCAR source strength model for pressurized liquid tanks where a stationary cloud or "mist pool" is predicted to form. When RAILCAR predicts a mist pool will form, you have the option of running the RAILCAR model or the traditional ALOHA tank model to estimate the source strength values (i.e., release rate, duration, and amount). No additional inputs are required to run the portion of the RAILCAR model that is available in ALOHA. The RAILCAR model was developed by the Navy, based on the results of field tests that were performed to better estimate how ammonia and chlorine escape from transportation tanks that have been damaged.
  • Revised helps.
  • Made additional minor changes and bug fixes. 

Getting Help

You can report software bugs or obtain additional assistance by emailing the RMP Reporting Center (, or by calling the CAMEO help desk at (703) 227-7650 on weekdays from 8 AM to 4:30 PM, Eastern Time.