Orders are pouring into Columbia Steel Casting in North Portland. With the national economy surging, manufacturers are eager for the company's steel and iron components.

There's a problem, though: the economy is so good here in Oregon that Columbia Steel can't find enough workers to accommodate the growing demand. Columbia has 50 open positions at its 86-acre campus and it can't expand until it fills those jobs.

"It stops us from growing but it's even making it difficult for us just to meet current customer demand," said Martha Cox, Columbia Steel's chief executive.

With Oregon's jobless rate at a record low, a state report out this past week finds employers all over Oregon are struggling to attract applicants.

Columbia Steel pays a starting training wage of $17 an hour, plus health benefits, and still can't fill its openings. Cox said Columbia struggles even to import workers from other parts of the country because Portland's housing costs are so high.

"When the unemployment rate has been as low as it has been for as long as it has been it's difficult," she said, "but not usually this difficult."

Oregon's worker shortage is a great situation for the dwindling number of out-of-work Oregonians. But economists worry it could signal long-term economic problems if hiring constraints stop businesses from growing.

"Could it be slowing the economy? Yes, I think it is," said Oregon state labor economist Nick Beleiciks, who authored the report. He notes job growth that topped 3 percent annually two years ago is growing by about 1.9 percent.

The number of hard-to-fill Oregon job vacancies is up 150 percent over the past five years, according to Beleiciks' survey. Employers say nearly two-thirds of all jobs are hard to fill.

Lake Oswego manufacturer Gunderson wants to hire 100 people to make its railcars and barges.

"It's a rather tall order for us," lamented Gunderson human resources director Kevin Moore, who wants to hire 100 workers. He said it's very hard to lure workers away from their current jobs.

When promising candidates do come in, he said Gunderson has to lock them up right away or risk losing them altogether.

"If we don't act quickly enough to get people through the process, people are going to go and take another job," Moore said.

Oregon's unemployment rate has been at or near 4.1 percent, its lowest point on record, for 17 consecutive months.

The state survey found it's relatively easy to hire in densely populated Multnomah and Washington counties, where employers rate about half of job openings as difficult to fill. It's a different situation in Clackamas County and the sparsely populated Oregon coast, where employers struggle to fill three-quarters of their openings.

Survey respondents cited a variety of reasons: lack of experience, absence of specific qualifications and a general lack of reliability from prospective hires.

Oregon's steadily growing economy has been pulling jobless people back into the work force for several years. Economists say those still not working may have out-of-date skills or simply be rusty.

Additionally, a growing number of employers say prospective hires cannot pass a drug test.

That's a relatively small share of the hiring problem, according to the survey, accounting to just 4 percent of hard-to-hire situations. But that's 2 to 4 times more frequent than in survey responses from 2013 to 2016.

Recreational marijuana use became legal in Oregon in July 2015.

Puzzlingly, Oregon's job shortage hasn't resulted in a major boost in worker pay. Wages had been growing, Beleiciks said, but over the past year haven't been outpacing inflation.

It's possible wages are growing at the low end of the pay scale at a level too small to show up with Oregon's blunt measurement tools, he said. Or maybe money that might have gone toward raises is instead going to pick up rising health insurance costs.

Regardless, Oregon's worker shortage doesn't appear to be providing a big boost to incomes even as it constrains the economy.

"We have some people putting expansion plans on hold because they can't find enough people to do these jobs," Beleiciks said. "It's not good for businesses, and it seems to be slowing down the overall rate of growth."

Businesses need to adjust their expectations, according to Beleiciks, and perhaps their strategies.

"Employers are still looking for workers that have previous work experience," he said.

There are very few skilled workers at this point who want a job but don't' already have one. So businesses may have to accept the need for more on-the-job training.

"They've got to be more likely to take on inexperienced workers now because it might be the only way they can find workers," Beleiciks said.

ECONorthwest economist Bob Whelan has been warning for months that the lack of available workers could trigger a slowdown in Oregon's economy, and perhaps itself be the cause of the state's next recession.

The federal tax cuts approved last fall are saving Oregonians more than $1 billion a year, adding fuel to an already hearty economy. But given the worker shortage, Whelan said that's not necessarily a good thing – at least not on the macroeconomic scale.

"It's creates all this demand," Whelan said. "Well, that only works if there's enough slack in the economy. Well, now we have no slack in the economy."

The additional stimulus risks inflation, he said, replicating mistakes made during the Johnson administration in the 1960s. Whelan said that could trigger a downturn that is stubbornly difficult to reverse.

"It's just obvious to me," Whelan said. "It's like I'm watching a train wreck."

-- Mike Rogoway | twitter: @rogoway | 503-294-7699