JULY 10, 2015 -- The week of July 6, 2015, the newest version of the ALOHA hazard modeling program (version 5.4.5) was released.

You can use ALOHA to model toxic gas clouds, fires, and explosions to determine areas where key levels of concern have been exceeded and a threat to the public may exist.

This latest update to the program includes new data from several sources, including revised public exposure guidelines for toxic releases. ALOHA 5.4.5 also includes a new alternative source strength model to estimate how chemicals escape from tanks over time. The new model is called RAILCAR, and it was developed by the Naval Surface Warfare Center, Dahlgren Division.

The RAILCAR model was developed based on the results of the Jack Rabbit Test Program, which involved a series of field tests performed in 2010 in order to better estimate how ammonia and chlorine escaped from transportation tanks. The RAILCAR model simulates the release of pressurized liquid from a transportation or storage tank as a result of damage to the tank. RAILCAR predicts that pressurized liquids will not only form dense vapor clouds, but will pool at the release location under certain incident and meteorological conditions. The portion of the RAILCAR model that estimates the source strength associated with releases that form stationary clouds or "mist pools" is now available in ALOHA 5.4.5.

Download the ALOHA program here. ALOHA is part of the CAMEO software suite, which is developed jointly by NOAA and EPA.

For further information, contact Mark.W.Miller@noaa.gov.

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