BAR HARBOR — Citing figures they say demonstrate that The Jackson Laboratory is emerging from last year’s economic slump, lab officials ceremonially broke ground Wednesday on a new facility expected to help the lab expand one of its more profitable products.

The importation isolation building, which is being funded in part by a $4.7 million grant from the taxpayer-supported Maine Technology Asset Fund, would provide space for many of the lab’s reproductive services functions. The MTAF grant is paying for half of the building’s construction and the lab is funding the rest, lab officials said.

Charles Hewett, Jackson Lab’s chief operating officer, said Wednesday the lab’s mouse sales have recovered since the global economy went into a tailspin last fall. Besides conducting its own research on human disease and medical conditions, the lab breeds millions of mice each year that it ships to other research laboratories around the world.

Hewett said that since June 1, the lab’s revenue from reproductive services is 7 percent ahead of where it was this time last year. This has helped restore work hours for lab employees whose hours were cut last fall as a way to reduce the lab’s operating costs, he said.

“That is a very promising sign,” Hewett said. “All of our employees are back to a 40-hour work week, and we’re very excited about that.”

The lab laid off 55 employees last March due to the poor economy, but with more than 1,300 employees it remains the largest employer in Hancock County and one of the largest in eastern Maine.

According to Hewett, May was the lab’s best month ever as far as its reproductive services revenue, with more than $700,000 coming into the lab that month. Despite the economic slump, revenue from the lab’s reproductive services grew last year by 40 percent, he said. By next year, such revenues are expected to grow overall by another 20 percent.