Hawaiian Dredging Construction Co., one of the state's oldest and largest construction companies, has laid off about 70 workers because of the economic downturn, according to president William Wilson.

"Because of the slowdown in the construction industry, we reduced salaried and hourly staff as we do see there being less construction work for us," Wilson said.

He said most affected employees are union workers, although some professional, managerial and engineering people also were let go.

Wilson traced most of the job losses to two projects. He said the Country Club Village 6 project in Salt Lake — a residential high-rise near Moanalua High School — is wrapping up. And Wilson said the developers of the higher-end Moana Vista residential condominium in Kaka'ako are slowing down work on that project because of the market and holiday season.

Hawaiian Dredging is the latest in a string of local businesses that have been forced to cut their work forces since the economy began slipping earlier this year. Other layoffs have included: 1,900 at Aloha Airlines; 274 at Maui Land & Pineapple; 169 at Hawaii Medical Center; 130 at DFS Group retailer; 120 at Molokai Ranch; 85 at Weyerhaeuser Co.; 118 at Servo Pacific, 91 at The Honolulu Advertiser; and 38 at Palama Meat Co.

Wilson said just a few years ago — when construction and the economy were booming — the company peaked with about 1,200 employees.

Although he's seen the construction industry go through cycles in his decades in the business, the past few months are different, he said.

"The change in market condition is much more rapid than I've ever seen before," he said.

Wilson called the layoffs "gut-wrenching" for the the entire company.

He said the company is losing valued and longtime employees. He said the company hires people "in anticipation of employing them for a long time."

But, he said, current conditions have left the company without a choice. "Unfortunately, we do not control market conditions," he said.

"It's very difficult for all the survivors, too," Wilson said. "There's uncertainty for what lies ahead."

Founded in 1902, Hawaiian Dredging is now owned by Kajima USA. It is Hawai'i's oldest and largest full-service construction company. One of the company's first contracts after its formation was to widen the main channel of Pearl Harbor.

The Hawaii Business Top 250 listed the company this year at No. 14, with annual sales of $646 million. Wilson said the company continues to build a number of projects for the state, counties and Hawaiian Electric Co. And the company is the prime contractor for Walt Disney Parks & Resorts planned Ko Olina resort, a major project. Hawaiian Dredging began work on pre-construction activities at Ko Olina in January when it was selected as lead contractor.

Wilson said those jobs have allowed the company to absorb workers into those projects and have prevented loss of even more workers.