Amazon CEO Jeff Bezos said Thursday that the company is on its way to building the capacity to test all of its employees for the coronavirus.

In a shareholder letter, Bezos said that the e-commerce juggernaut is on the cusp of being able to begin tests on employees in its warehouses, and will eventually be able to test all workers regardless of whether they have symptoms.

“We have begun assembling the equipment we need to build our first lab and hope to start testing small numbers of our front-line employees soon,” he wrote. “We are not sure how far we will get in the relevant time frame, but we think it’s worth trying, and we stand ready to share anything we learn.”

Amazon has faced harsh criticism in recent weeks for the conditions its warehouse workers have been forced to toil under during the pandemic.

The company’s warehouses in areas hit hardest by the coronavirus — including New York, Detroit and Chicago — have seen employee protests in recent weeks amid reports that dozens of warehouse workers have fallen ill.

At the same time, Amazon has been forced to hire 100,000 new workers at its warehouses around the country — and announced earlier this week that it plans on adding 75,000 more — as demand for its products surge.

Bezos last week made a surprise visit to an Amazon Warehouse and Whole Foods supermarket, greeting employees and thanking them for their hard work. Amazon also recently began taking workers’ temperatures when they show up for their warehouse shifts.