The Land Board on Thursday unanimously approved a settlement agreement between the state and Denise and James O’Shea, who were accused in 2017 of building an illegal seawall on Sunset Beach that stands 15 feet tall, 46 feet long and 8 feet thick at its base.

The property owners will have two years to remove the hulking wall, which sits along one of the most famous beaches on Oahu’s North Shore.

Coastal experts say the seawall is contributing to beach loss, blocking public shoreline access and creating unsafe conditions by making it hard for lifeguards to access the coastline.

The seawall will have remained on the beach for seven years if the property owners use the full two years to remove it. The O’Sheas, or any future owner, also will be allowed to credit a $52,500 fine toward the cost of removing the seawall, under the agreement.

The Department of Land and Natural Resources took the O’Sheas to court seeking an order requiring them to remove the seawall. The O’Sheas filed a counterclaim alleging that the state had built a wall in front of their house before they purchased it. They argued that the wall collapsed in 2017 and that DLNR was required to maintain it to protect their oceanfront property.

DLNR says there is no rec­ord of the state building the collapsed seawall, and in any case, the O’Sheas built a completely new seawall without any permission from the state.

Seawalls, which have caused widespread beach loss throughout the islands, are largely prohibited under state law.

The state spent five years litigating the case. On Thursday, Michael Cain, who heads DLNR’s Office of Conservation and Coastal Lands, told the Land Board that the settlement agreement could help expedite removal of the seawall.

“This agreement gives us a hard deadline, the end of Dec. 2024, where that wall will be removed,” said Cain. “We are very confident that if this proceeds to trial we will win. However, we don’t know how many years that will take.”

The O’Sheas, who didn’t attend the hearing, listed their four-bedroom, two-bath house at 59-171-D Ke Nui Road for sale for close to $2 million six months ago, according to a real estate listing.

The settlement runs with the property, and any future owner also will be subject to the Dec. 31, 2024, deadline for removing the seawall.