Gwinnett County transit workers are threatening to walk off the job Thursday over fear for their safety amid the coronavirus pandemic — even as a second metro Atlanta transit worker has died.

In a Monday letter to the transportation company Transdev, which operates the Gwinnett County Transit service, the employee union cited unsafe working conditions and a lack of adequate protective equipment for bus drivers.

Among other things, the union says bus drivers want clear shields to separate drivers from passengers, and they want the transit system to require passengers to wear masks. The union also says proper social distancing is not being followed on paratransit buses.

A Transdev spokesman said the agency and the county “have been closely collaborating to address the emerging situation.” She cited numerous steps the company has taken to protect workers.

Meanwhile, a supervisor at CobbLinc died Sunday from COVID-19. He is the second metro Atlanta transit worker to die from the disease caused by the coronavirus, after the death of a MARTA employee last week. A spokesman for Cobb County confirmed the death, which happened Sunday, but provided no details.

The private company that operates CobbLinc, First Transportation, did not immediately respond to requests for comment.

“Cobb County’s Department of Transportation family is deeply saddened to learn of the loss of one of our team members,” Transportation Director Erica Parish said in a statement released to The Atlanta Journal-Constitution.

She said the employee tested positive for the disease April 17, and a team immediately cleaned the facilities where he worked. Other employees who worked with him were tested and isolated. A county spokesman said First Transportation has not notified Cobb County of any additional positive tests.

The developments in Gwinnett and Cobb underscore the vulnerability of transit workers as local agencies seek to keep public transportation running amid the pandemic. Transit agencies say many low-income residents and essential workers rely on their services to get to jobs, medical appointments, grocery stores and other destinations.

But dozens of transit workers across the country have died from COVID-19, including the two in metro Atlanta.

Mikesha Walker, a Gwinnett bus driver and transit union representative, said workers fear for their safety amid the pandemic.

“They’re scared to death,” she said. “It’s terrifying.”

Walker said those fears have been heightened by Gov. Brian Kemp's decision to begin allowing businesses to reopen. Though the number of passengers has plummeted as residents shelter in place, employees worry Kemp's decision could bring a flood of passengers back to buses — exposing drivers to more risk.

Walker said employees do not plan a strike or “sickout.” Instead, they will report to work Thursday. If they deem conditions to be unsafe, they will refuse to work, as allowed by federal law.

“They’re hurt, they’re scared, they’re angry,” she said. “They feel unsafe.”

The employees also recently asked for hazard pay, though Walker said they have not received it.

Mitun Seguin, the Transdev representative, said the company has taken numerous steps to address safety and other concerns.

She said fixed-route bus drivers in Gwinnett are now working about 48 hours every two weeks, but the company is still paying them for 80 hours. She said buses are limited to 10 passengers, and they must board at the rear door, separating them from drivers. And seats behind the driver are blocked off.

Seguin said Transdev has “launched an extensive campaign to inform passengers that we recommend they wear masks when they ride public transportation.” Among other things, the company also has limited paratransit reservations so that no more than two passengers are booked for a vehicle at once, and it has stepped up cleaning of vehicles and facilities.

Seguin said the company has not had any confirmed coronavirus cases in Gwinnett, though the company allows leaves of absence for employees who have expressed concerns or are considered to be at high risk for the virus.

Gwinnett County referred questions about the details of the health and safety concerns to Transdev. But spokesman Joe Sorenson said the county’s “top priority is the health and safety of the drivers, the passengers and the community at large.”