Boeing Co., which said Monday it will idle the rest of its civilian jet airliner plants in the Seattle area for the next two weeks, is keeping production lines running for its Osprey vertical-takeoff craft and Chinook helicopters in Ridley Park, Delaware County, the company said.

To be sure, all staff among the Ridley Park plant’s 4,600-plus workers who can work from home will “telecommute until further notice,” Boeing said in a statement Monday. About a third of employees work the assembly lines. Others include engineers, administrative workers, sales and marketing personnel.

Boeing employs 70,000 in the Seattle area. The company had hoped to avoid layoffs when it closed its Renton, Wash., plants in January amid collapsing sales for its 737 Max jet airliners, whose control system was implicated in two lethal crashes in the last year and a half. Besides in Ridley Park, Boeing is also keeping open its jet aircraft works in South Carolina, which employ about 6,800 making 787 jet airliners.

Though the company borrowed an additional $14 billion on top of its previous large debt load last month, Boeing has “about $10 billion of cash” still on hand. It has also suspended its $4.6 billion yearly shareholders’ dividend and should stay solvent long enough to qualify for expected federal assistance once a corporate aid package passes Congress, Standard & Poor’s analyst Christopher DeNicolo reported to clients.

Two other Philadelphia-area helicopter factories that sell to both the government and civilian users have also remained open, with non-production workers operating from home.

In Northeast Philadelphia, Leonardo Helicopters — like Boeing classified a “critical defense infrastructure" plant by the U.S. government and the state — also remains open, though more than half the 600 staff members are working from home, and extra cleaning measures, emergency sick leave, and travel restrictions have been imposed, spokeswoman Margaret Rogalski said Monday.

Similar conditions are in force at Lockheed Martin’s Sikorsky helicopter factory in Coatesville, according to spokeswoman Callie Ferrari in a statement last week. That plant employs about 450. The company has about 5,000 workers at its military systems offices in King of Prussia, Moorestown, and other area locations.

In Delaware, a factory complex shut last week due to coronavirus reopened Monday. The Bloom Energy fuel cell factories in the Newark area, subsidized by state residents through a tax on their utility bills, were shut last week “to safeguard our employees and to investigate a potential employee exposure to COVID-19 offsite,” spokeswoman Natalia Blank said.

“After a thorough cleaning,” she added, “we reopened the plant [Monday] morning.”

Other employers, including Wawa convenience stores, have also had to close for cleaning before reopening.