BATH — Bath Iron Works, one of the state’s largest employers, announced Monday that two more workers have  tested positive for coronavirus, making six total cases at the shipyard since the pandemic reached Maine in March.

These two new positive cases were tied to the shipyard’s fourth positive case, announced last week. The company said the workers had been carpooling together.

“The Maine (Center for Disease Control and Prevention) classifies three related cases as an ‘outbreak’ and has done so in this situation,” wrote BIW Spokesman David Hench.

“We are working closely with the Maine CDC and have urged employees to practice COVID-19 safety guidelines with a renewed sense of dedication in light of this new information,” Hench wrote. “We are especially urging employees to abide by state restrictions on carpooling and to check their temperature daily prior to coming to work and to stay home if they have a fever or any other symptoms of COVID-19.”

The company also strongly recommended any employee who worked in the Combat Information Center tactical room in the future USS Carl Levin — a destroyer now under construction at the Bath shipyard — from June 15-29 be tested for the virus.

The company also recommended that anyone participating in the picket line at the main yard in Bath from June 22-24 be tested as well. For over a week, the largest union at BIW has been on strike of issues related to seniority and outsourcing.

The company would not release any additional details about the workers who most recently were diagnosed with COVID-19, but said they haven’t been to work since June 18 and 19, respectively. Both are self-isolating and receiving medical care.

The first case at the shipyard was in late March. Another case followed in early April, the third case was announced earlier this month and the fourth came last week. The first three workers who tested positive have recovered and returned to work, according to a statement from the company.

In March and April, as the number of cases in Maine steadily rose, union officials and Maine lawmakers called on the company to close to prevent the virus from spreading within the shipyard, which employs 6,700 people from every county in the state. The shipyard stayed open, but ramped up cleaning and encouraged employees to start wearing masks or face shields when close to other workers.

“At Bath Iron Works, the safety of our employees continues to be our top priority, and we are committed to supporting them as we navigate these unprecedented times as an industry essential to the defense of our nation,” the company said.

Employee attendance plummeted after that initial test, with only 41 percent of workers clocking in two days after the shipyard announced the first positive test.

Fewer than half of the shipyard’s employees are clocking in as the company’s largest union continues to strike for changes to its new contract. However, nearly all picketers have decided against wearing a face mask while picketing, though the CDC recommends masks in public because the virus is believed to spread through respiratory droplets.

The Maine CDC has recorded 3,221 cases since mid-March. Of those, 2,593 people have recovered and 105 people have died, leaving 523 active cases, the Portland Press Herald reported.