CHARLESTOWN — Beyond complex legal sparring, federal appeals court proceedings on Tuesday revealed a few new details about the prospect of the U.S. Department of Interior taking 31 acres just north of Route 1 into trust for the Narragansett Indian Tribe.

The Interior Department agreed to place the sloping property into trust for tribal housing in 1998. The state and the Town of Charlestown have since appealed in federal court in a case that worked its way up to the full 1st U.S. Circuit Court of Appeals in Boston on Tuesday.

Trust status would free the land from most state and local laws and taxes. It would fall, instead, under federal and tribal authority.

Chief Sachem Matthew Thomas said the site will be used for housing for the tribe’s poor elderly members. Work began on 12 units, but uninhabitable shells are all that remain after nearly a decade of legal tangling and internal strife.

“As far as I know it will be used for housing,” Thomas said in court Tuesday.

But a Department of Justice lawyer, representing the Interior Department, told the court that could change.

“The use doesn’t need to be housing forever. The tribe has the right” to revise its plans, said Elizabeth Ann Peterson.

Some town and state officials fear the tribe might try to build a casino or other industry on the land — a concern that was echoed in court Tuesday.

Under federal law, Indian lands can be used for gaming only if they were taken into trust before 1988, or if the property is within or contiguous to a tribe’s reservation. The tribe would also need to enter into a compact with the state in which its lands are located, but the federal government could weigh in if an agreement cannot be reached.

Though the land sits across the road from the tribe’s other 1,800 acres, the larger property is bound by state civil and criminal laws under a 1978 land claims settlement. Additionally, the late Sen. John H. Chafee introduced a federal law in 1996 that barred the Narragansetts from the privileges of federal Indian gaming law on its 1,800 acres.

The state has argued that the laws that apply to the tribe’s 1,800 acres should also stand on the housing site under the 1978 agreement. Lawyers say the Narragansetts gave up all future land claims in the state of Rhode Island under that deal — a contention Department of Justice lawyers dismiss.

The circuit judges touched upon the prospect of a casino and other possibilities Tuesday.

The Narragansetts for years have tried to open a gaming venue in Rhode Island. Voters in November decidedly rejected a referendum that would have allowed the tribe to build a casino in West Warwick.

Judge Bruce M. Selya asked what rights the state would have to enforce its health and safety codes should the tribe decide to build a factory.

If the land was placed in unrestricted trust, it would fall under the tribe’s civil and regulatory jurisdiction, said Peterson, of the Justice Department. The state and other parties could raise environmental concerns in federal court.

“Federal courts decide issues of Indian Country,” she said.

Judge Kermit V. Lipez inquired whether the state could instead approach the Department of Interior with concerns. “Does the department have any leverage over the tribe?” he said.

“We hold legal title. The tribe has authority on its land,” Peterson said.

Peterson told the court that the Department of Interior weighed such considerations as the tax impact on the state and the environment in deciding to place the land into trust. Though an environmental study was done regarding the housing project, no further studies would be undertaken if the property’s proposed use changed, she said.

Judge Sandra L. Lynch questioned what would happen if a tribal member murdered a non-Indian, such as a sewer repair guy, on trust land.

The U.S. Attorney’s office would handle such a case, Peterson said.

Richard Guest, a lawyer for the Native American Rights Fund, yesterday took issue with representations that the 31 acres would be stripped of Rhode Island laws “as if it would become a land of lawlessness.”

Tribes do not have authority over non-Indians who commit crimes on lands held in trust. Those would be prosecuted by the state. Tribes are only empowered to handle misdemeanor, or lesser, crimes among their members. “Major crimes are handled by the United States,” he said.

The presumption seems to be that the tribe would do something illegal, said Guest, who attended court.

“That’s stereotyping,” he said.

Discussion missing from the proceedings was that tribes generally do not pursue projects that would be detrimental to the environment, he said.

“If someone could point me to an example, then let’s take a look at it,” he said. Though pondering what might become of the Narragansetts’ land is speculative, parties that object to a tribal pursuit can seek recourse in the court or, as seen with the Chafee Amendment, through Congress, he said.

Guest flew in from Washington, D.C., to observe the case because of its potential impact on more than 40 tribes nationwide. The state is arguing that the federal government cannot place the land in trust because the Narragansett tribe was not federally recognized when Congress passed the Indian Reorganization Act in 1934. That law was intended to restore land and extend certain services to Native Americans. The Narragansett tribe was recognized in 1983.

“A tribe is a tribe is a tribe is a tribe. They’re all tribes,” Guest said of the federal government’s position.

Charlestown Town Council President Kate Waterman said she was heartened by the judges’ interest in the potential environmental and human consequences associated with the 31 acres.

She worries that allowing the land to be taken into trust could open the door for the tribe to acquire other lands across the state that, in turn, could be taken into trust and removed from state jurisdiction.

“With access to large sums of money [from gambling proceeds]. They can buy a lot of land and put it into trust. It should alarm people. The ponds will be gone,” Waterman said.

She reiterates a position held by Charlestown’s solicitor on Indian affairs, Joseph S. Larisa Jr.

“This will open up the potential for Indian Country all over the state of Rhode Island,” he said Tuesday.

Waterman added that she would like to see the tribe pursue a windmill farm as an environmentally sensitive, energy conscious alternative on the land. The town, she said, is not opposed to seeing economic development for the tribe.

The tribe bought the 31 acres in 1991 for housing for its elderly. That project, mired by mismanagement, stalled when the tribe began construction without securing state and local permits. The property has since been at the heart of a legal battle with the state.

Another obstacle is a 1995 federal court order forbidding the tribe to do any work that would interfere with a town drainage easement across the site. The town has refused to abandon the easement in exchange for a slice of tribal land because the tribe will not sign an agreement saying it will treat the 31 acres like its other lands.

Fourteen of 17 tribal elders who were placed on the waiting list for housing when the project began have since died, said tribal member Paulla Dove Jennings.