The U.S. Environmental Protection Agency has just made it easier to legally convert light- and heavy-duty vehicle conversions to alternative fuels, such as compressed natural gas.
Manufacturers can now more readily sell conversions thanks to an exemption found in a 186-page EPA ruling that overrides previous rules against tampering when converting an engine.
The former rules required alternative-fuel conversion systems to be certified in the same stringent manner to which an original manufacturer would have to comply. This bureaucratic quagmire was difficult and expensive, thus creating a high barrier to entry.
A streamlined testing procedure now makes it simpler to comply. In short, depending on the age of the vehicle to be converted, retrofitted vehicles now only have to pass a graded compliance structure. More details can be seen in the EPA link below.