Tyson Foods greatly increased the amount of frozen chicken strips it recalled to about 12 million pounds, after four more people complained about finding metal pieces.

Those complaints add on to two reports that prompted the original recall March 21 of about 70,000 pounds. Three complaints alleged oral injury, according to the USDA’s Food Safety and Inspection Service.

Tyson said in a statement that it is expanding the recall to chicken sold nationwide in the interest of public health, even though the complaints only involve a small number of products, and the “vast majority” of chicken has been consumed without reported incidents.

“It is unacceptable to Tyson Foods that any product might not meet our standards. Because of these additional consumer reports, we’ve decided to take this precautionary step to make sure that we’re meeting our own expectations and the expectation of consumers,” says Barbara Masters, vice president of regulatory food policy, food and agriculture for Tyson.

The company has stopped using equipment believed to be associated with the metal fragments, and it will install X-ray metal detecting machines to replace its metal detection system, Masters says. A third-party video auditing system will verify the metal detection.

The products shipped to stores nationwide were made from Oct. 1, 2018, through March 8, 2019, and have use by dates of Oct. 1, 2019, through March 7, 2020. Chicken strips sold under some private brands, including Meijer and Food Lion, also were recalled. See the full list here.

The packages have establishment No. P-7221 on the back. The items also were shipped to Department of Defense locations nationwide, for institutional use nationwide and to the U.S. Virgin Islands.

People should throw away the products or return them. Anyone with questions about the recall can call Tyson Foods at 866-886-8456.