A press official for MOL confirmed the authenticity of the letter, dated Oct. 5 and published by the mayor on Facebook.

The letter said the 200 infected workers have been quarantined and had no symptoms. MOL said work at the construction site was ongoing with reduced staff levels.

The $1.3 billion plant, built by Germany's ThyssenKrupp, will make MOL the only integrated producer of polyether polyols in Central and Eastern Europe.

The compounds are needed for products in the automotive, construction, packaging and furniture industries.

MOL said in the letter it was testing its blue-collar staff for coronavirus every two to three weeks and expected to test all white-collar workers by the end of this month. MOL said it expected subcontractors to test their staff as well.

As of Tuesday, Hungary reported 32,298 coronavirus cases with 853 deaths and 8,723 recoveries. New cases have spiked in the past weeks and the 20 deaths registered on Tuesday were the highest since the start of the pandemic.

(Reporting by Gergely Szakacs; Editing by Tomasz Janowski)