Tesla (TSLA) has denied reports of coronavirus transmission at its plant in Fremont, California, with CEO Elon Musk having been frequently criticized for his response to the pandemic. 

“Since we restarted operations, we have had zero COVID-19 workplace transmissions. COVID-19 exposure has occurred outside the workplace primarily through family members or housemates, and in most instances, the employee followed safety protocol, informed their manager and stayed home or went to get tested,” an internal email from Tesla safety chief Laurie Shelby to employees reportedly said.

The message from Shelby did not explain how Tesla came to these conclusions of "zero" employee transmission. 

On Tuesday, two anonymous Tesla employees told the Washington Post that “several cases” of the virus had been confirmed at the Fremont plant and a seat-assembly factory nearby. Employees told CNBC this week that it is impossible to build cars at the plant and comply with local safety regulations amid the pandemic.

An anonymous worker told Electrek that Tesla has taken minimal efforts to protect employees from the virus. 

“We’re still working on top of each other,” the worker told Electrek. “All they do is make us wear a mask in a hot factory. They take our temperature and have us use hand sanitizer when we walk in. But obviously, that isn’t working.”

The Fremont plant is located in Alameda County, where Musk has frequently clashed with the county’s public health department. Musk initially refused to close down the factory in mid-March when the county implemented a shutdown order. In May, Musk moved to sue the county if officials would not let him reopen the plant. Musk has called the shutdown orders “fascist” and said they pose a “serious risk” to Tesla’s business.

Shares of Tesla reached an all-time high this week, reaching $1,027.48. Tesla shares closed at $935.28 on Friday. 

Musk has not directly referenced the company's share price this week on Twitter. “Tesla stock price is too high [in my opinion],” Musk posted on Twitter on May 1, when the company was valued at $140 billion.

On Friday, Goldman Sachs and Morgan Stanley downgraded Tesla due to the company cutting prices on several models, along with concerns about near-term demand and trade tensions between the U.S. and China.