It is now available on the web, and has been available for PDAs for some time. There is key information, and links to further information in other NLM resources, if you know what the substance is. There is also information on protective clothing, protective distance, and treatment, among other things.
Or you can search WISER using information about state, colour, taste, and various chemical properties, in order to identify what it is, if you don't. Results are refined as you add properties to your search and you can view results at any time.