NOVELTY - At least one gas comprising at least hydrogen gas is produced by converting in a reactor a portion of hydrocarbon feedstock(s) to carbon black in the presence of combustion gases generated by burning a fuel in a gas comprising oxygen, where the carbon black is present in a product stream that comprises carbon black, one or more impurities, hydrogen gas and carbon monoxide gas; removing all of the carbon black from the product stream; and removing a portion of the impurities from the product stream.    USE - The inventive method is used for producing at least one gas, where the gas comprises at least hydrogen gas.    ADVANTAGE - The inventive method effectively runs the process such that efficient quantities of hydrogen gas are produced, along with economically useful amounts of carbon black. It provides a "green" operation, which significantly reduces the emissions of gases to the environment, including sulfur emissions. It can be achieved with or without diverting any portion of the product stream to the hot combustion gas stream or to the fuel stream or oxygen stream. It preferably produces the product stream, after removing the sulfur-containing material, which has a very low sulfur amount. It permits the ability to produce useful quantities of carbon black along with the useful quantities of hydrogen gas or hydrogen gas and carbon monoxide. The quality of the carbon black, as well as the quality of the hydrogen gas alone or with carbon monoxide, is preferably also commercially acceptable. The inventive method permits a useful combination of carbon black manufacturing with hydrogen gas production and by achieving both, a "green" process is developed which can permit the significant reduction in emissions, e.g. tail gas emissions, as well as sulfur and/or nitrogen emissions, e.g. at the location where the process is taking place. In addition, it permits a very economical use of the combined facility to avoid waste.    DETAILED DESCRIPTION - Production of at least one gas, where the gas comprises at least hydrogen gas, includes:    (A) in a reactor, converting a portion of hydrocarbon feedstock(s) to carbon black in the presence of combustion gases generated by burning a fuel in a gas comprising oxygen, where the carbon black is present in a product stream and the product stream comprises carbon black, one or more impurities, hydrogen gas and carbon monoxide (CO) gas, where the impurities comprise sulfur-containing material and/or nitrogen-containing material, and where the fuel is a portion of the hydrocarbon feedstock or a separate fuel source;    (B) removing all of the carbon black from the product stream; and    (C) removing a portion of the impurities from the product stream.    An INDEPENDENT CLAIM is also included for carbon black produced by the above production method.    DESCRIPTION OF DRAWING(S) - The figure is a flow diagram showing a method of producing at least one gas comprising at least hydrogen gas.