In its ruling, the court said that Berkeley's 2019 ban on gas hookups in effect banned all appliances operating with natural gas, which it cannot do because federal legislation pre-empts such local legislation, Reuters reported.

"By its plain text and structure, EPCA's preemption provision encompasses building codes that regulate natural gas use by covered products," Judge Patrick Bumatay, one of a three-member panel at the 9th Circuit Court of Appeals, wrote. "And by preventing such appliances from using natural gas, the new Berkeley building code does exactly that."

Berkeley is one of about a dozen cities around the United States that are basically waging war on natural gas and choosing to do it by banning the use of the fuel for household needs and, in some cases, business needs such as in restaurants.

Berkeley, however, was the first. Several major cities, including Denver, New York, Seattle, and San Francisco, have followed in Berkeley's example. The governments of the states they are in, in turn, have struck back with legislation banning such prohibitions.

For the proponents of gas bans, the benefits are clear, or rather, the benefit: lower emissions. For the opponents, there are too many disadvantages, from the cost of switching a house from gas to electricity to the effect of more all-electric households on the grid when the ban only applies to newbuilds.

The news about Berkeley would be welcome by the gas industry, which has been naturally opposing the string of bans, and by restaurants, for which natural gas is the most efficient and cheap option.