ALOHA® is the air hazard modeling program in the CAMEO® software suite developed jointly by NOAA and the Environmental Protection Agency (EPA), and it runs on both Windows and Mac computers. 

Based on your information about a chemical release, ALOHA’s source strength models estimate how quickly the chemical will escape from a tank, puddle, or gas pipeline and form a hazardous gas cloud—and also how that release rate may change over time.

An ALOHA threat zone estimate displayed on a MARPLOT map. The red, orange, and yellow zones indicate areas where specific Level of Concern thresholds were exceeded.

ALOHA can then model how that hazardous gas cloud will travel downwind—including both neutrally buoyant and heavy gas dispersion. Additionally, if the chemical is flammable, ALOHA also models pool fires, BLEVEs, vapor cloud explosions, jet fires, and flammable gas clouds (where flash fires might occur).

ALOHA produces a threat zone estimate, which shows the area where a particular hazard (such as toxicity or thermal radiation) is predicted to exceed a user-specified Level of Concern (LOC) at some time after the release begins.

The threat zone estimates are show on a grid in ALOHA, and they can be plotted on maps in MARPLOT®, Esri’s ArcMap (using MARPLOT to generate shapefiles), and Google Maps and Google Earth (using ALOHA’s KML Export).

• Download ALOHA 5.4.7 for Windows [EXE, 7.33 MB]
• Download ALOHA 5.4.7 for Mac [DMG, 9.63 MB]; additional Mac instructions

ALOHA 5.4.7 was released in September 2016. The Windows version can be run on the Windows 7, Windows 8.1, and Windows 10 operating systems. The Macintosh version can be run on the Mountain Lion (10.8), Mavericks (10.9), Yosemite (10.10), and El Capitan (10.11) operating systems. Other operating systems have not been tested and are not supported.

If you already have an older 5.4.x version of ALOHA: It is best to install the new ALOHA program in the same folder as your previous version. This will replace the old program 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.

• Updated chemical library, including new Design Institute for Physical Properties chemical data and new toxic Levels of Concern (Protective Action Criteria and Emergency Response Planning Guidelines).
• Made minor update to the RAILCAR source strength model for pressurized liquid tanks where a stationary cloud or "mist pool" is predicted to form.
• Revised helps.
• Made additional minor changes and bug fixes.

Significant changes in all versions of the program are available in the ALOHA development history.

• ALOHA Fact Sheet [PDF, 471 KB]: Learn more about program features by reading this ALOHA fact sheet.
• ALOHA Examples [PDF, 1.9 MB]: Download a training document with three step-by-step fictional ALOHA example scenarios.
• Ask Dr. ALOHA: Get to know ALOHA better by reading this series of informational articles that discuss key program features and walk through sample ALOHA scenarios.
• Met Station Vendor List: Look though a list of vendors of portable meteorological stations designed to work with ALOHA and find out how to design a met station for ALOHA.
• ALOHA Technical Resources: Review these documents if you are interested in developing a program or tool to work with ALOHA or if you want to learn about the equations that ALOHA uses.
• CAMEO News Service: This mailing list provides a way for the CAMEO team (at EPA and NOAA) to communicate important information to the CAMEO community. It is used primarily to send updates when new releases are available for ALOHA, CAMEO Chemicals, CAMEO Data Manager, MARPLOT, and/or Tier2 Submit. The service is hosted by NOAA. Follow this link to subscribe.
• CAMEO Software Suite: Find out more about the four core programs—and several related programs—in the CAMEO software suite, which aids in hazardous material response and planning.

Questions: Contact us with questions, comments, or suggestions about ALOHA.