While Gov. Tom Wolf continues to take steps to join the Regional Greenhouse Gas Initiative, a cap-and-trade program on greenhouse gas emissions, legislative Republicans continue to argue Wolf doesn’t have the power to join RGGI.

On Tuesday, the Wolf administration issued a final rule for the regulatory plan with the same timeline and same goals for reductions in carbon dioxide. It was the latest step in two years of work by Wolf and his appointees to join RGGI, the 11-state consortium of Northeastern and mid-Atlantic states that sets a price and declining limits on carbon dioxide emissions from power plants.

If Wolf is successful, Pennsylvania would become the first major fossil fuel state to adopt a carbon pricing policy and join the Regional Greenhouse Gas Initiative, called RGGI. Wolf has made both a centerpiece of his strategy to fight climate change in one of the nation’s biggest power states and polluters.

According to the Associated Press, the rule must still go through two state regulatory boards with veto power, although both are tilted toward Wolf appointees and allies.

On Tuesday, Rep. Daryl Metcalfe, R-Butler and House Environmental Resources and Energy Committee chairman, convened a voting meeting to approve a letter to the Regional Greenhouse Gas Initiative stating Wolf doesn’t have the authority to join RGGI without legislative approval.

“At this point, you have likely already spent a great deal of time and resources planning for Pennsylvania’s entry into RGGI. It is unfortunate that our governor has put you in this position by proceeding so far down this path without obtaining legislative approval for his actions. We would urge you to make it clear to the DEP and the governor’s office that you will not be wasting any more energy on this project until it is made clear that Pennsylvania will actually be joining by an act of our legislature,” Metcalfe’s letter states.

Just last month, Republicans threatened to block confirmation of Wolf’s appointments to the five-member Pennsylvania Public Utility Commission — which regulates public utilities, but not power plants or pollution — if Wolf did not agree to seek the Legislature’s approval first to join RGGI.

Power plants fueled by coal, oil or natural gas with capacity of 25 megawatts or more in RGGI states have to buy a credit for every ton of carbon dioxide they emit. Supporters of the RGGI program say the required credits have forced innovation to decrease carbon dioxide emissions, including retirement of coal plants and a greater focus on renewable energy, in order to avoid purchasing credits.

The cost of credits would generate an estimated hundreds of millions of dollars annually for the state in Pennsylvania. Republicans say the credits are a tax that can only be levied by legislative action. Administration officials, according to the Associated Press, counter by saying spending the money would require legislative approval only if the spending goes beyond pollution-reduction programs allowable under the Air Pollution Control Act.

The Associated Press recently reported that Pennsylvania emitted 222 million tons of carbon dioxide in 2018, or fourth-most among states, according to statistics from the U.S. Department of Energy’s Energy Information Administration. Electric power production accounted for 74 million tons, or 33.5% of that, just ahead of the transportation sector, according to federal statistics.

— The Associated Press contributed to this article.