IOWA CITY, Iowa (AP) — A safety regulator praised Tyson Foods for providing a quick written response after learning about a complaint alleging the coronavirus was spreading at its plant in Perry, Iowa before an outbreak was confirmed there.Iowa Occupational Safety and Health Records obtained by The Associated Press show the agency received the complaint April 11, did not contact Tyson until April 20 and gave the company one week to respond. Tyson released records Tuesday showing that it responded two days after learning of the complaint and a state official praised its “diligence.”

The agency closed the inquiry April 28 after determining that Tyson’s response outlining its safety efforts at the plant was satisfactory. Later, 730 workers at the plant tested positive for coronavirus.