For a maker of boom trucks in Duluth, business is quite literally booming.

In the past few years, Altec HiLine LLC's work force in Duluth has swelled from about 50 to more than 70 people, and Dave Faynik, general manager of the plant, says he's not done hiring.

"I expect to see continued growth this year, but I'm not sure how many more people we will need," he said, adding, "The future looks bright."

Altec HiLine designs, builds and services boom trucks for the utility industry. It's a wholly-owned subsidiary of Altec Inc. , a Birmingham, Ala .-based company with about 2,500 employees. Altec manufactures a wide range of aerial lifts, as well as digger derrick trucks and specialty equipment for the electric, telecom and tree-care industries.

Although the Duluth plant usually is dedicated to the production of boom trucks, lately it has picked up additional work manufacturing digger derricks. The move has helped Altec HiLine's parent company meet surging demand for equipment after one of the country's most destructive hurricane seasons.

The additional work has caused Altec to outgrow its production floor. This month, the Duluth Seaway Port Authority agreed to lease the company an additional 26,000 square feet of space, boosting its total presence in a building at the Arthur M. Clure Public Marine Terminal to about 90,000 square feet.

In 3 years, sales have tripled, Faynik said.

"The additional business we've been getting is a testament to the quality of the team we have working here," Faynik said. "We've demonstrated that we can build high-quality units competitively and deliver them on time."

<In a typical day, three finished digger derricks roll off the line in Duluth. The units, which are used to install utility poles and perform other service work, usually sell for $100,000 to $130,000 apiece.

Workers at the Duluth plant also continue to build boom trucks. The largest of these booms can reach heights of 150 feet, and they sell for $700,000 to $800,000 . Altec HiLine generally completes work on two to five boom trucks per week.

These booms are made with insulated fiberglass sections that prevent electrical grounding. Faynik explained that the boom trucks are often used to service live high-power lines, sometimes carrying as much as 500,000 volts. Using such a boom, a worker can tie into a live wire and work without injury, much as a bird is able sit on an energized wire.

Altec isn't the first company to manufacture such booms in Duluth. It acquired the assets of NorStar Products International 3 years ago largely because of its interest in the niche the Duluth company had found in the power industry.

The Port Authority helped NorStar develop its line of aerial extension boom trucks by providing a $300,000 loan to the company in 1999.

"It became the machine of choice to maintain and build transmission lines," said Kelly Herstad , a Duluth businessman who was NorStar's majority owner.

The equipment put NorStar on the map and attracted attention not only from Altec but from another suitor. Herstad said this competitor offered to buy out his company for a higher price, but it planned to close the plant in Duluth and move production to South Dakota . Wanting to see the jobs stay in Duluth, Herstad went with Altec .

Andy McDonough , business development director for the Port Authority, said that Altec , as a well-capitalized company with a large national presence, has brought stability to the local manufacturing plant.

Herstad was part of an investment group that acquired some of the assets of Reach All, a Duluth manufacturer of aerial platforms and utility equipment, when the troubled company disintegrated in 1995.

Looking back, Herstad called his decision to get involved in the business "an impulsive moment." But he's glad he did.

McDonough said that were it not for Herstad and his partners, the portion of Reach All that became NorStar and later Altec HiLine could have been completely dismantled.

"The whole thing very well could have imploded," McDonough said. "All these jobs could have left the area, and we could have been left with nothing more than an empty building."