The FDA has announced that the safety concerns with syringes manufactured in China are more extensive than previously believed.

• The FDA has updated its safety communication regarding Chinese-made plastic syringes in the U.S., stating that the issues are "more widespread" than previously believed.
• Three Chinese-based syringe manufacturers were found to have violated FDA regulations: Jiangsu Shenli Medical Production Co. Ltd, Medline Industries LP, and Sol-Millennium Medical Inc.
• The FDA data reviewed by CNBC reveals that major medical manufacturers are distributing syringes made in China.

The FDA issued a warning on Tuesday about Chinese-made plastic syringes in the US, stating that there are more widespread quality control issues than previously thought.

The FDA discovered that three Chinese syringe manufacturers were in violation of its regulations.

CNBC has been investigating the issue of quality and performance problems with plastic syringes made in China since November, when the FDA first announced its review of such reports. After months of inquiry, the agency recently released an updated safety communication confirming that the issues are more widespread than initially thought.

The FDA issued warning letters to three Chinese manufacturers and two firms marketing and distributing unauthorized plastic syringes made in China that are not cleared by the FDA for use in the U.S. on March 18.

In 2023, the agency received over 4,000 reports about plastic syringe problems, which were not limited to syringes made in China. However, the agency noted that there were limitations to this data, including incomplete information in the reports and potential under-reporting.

CNBC reviewed hundreds of narratives for syringe medical device reports (MDRs) submitted to the FDA, which are designed to highlight suspected issues or malfunctions associated with medical products as part of its monthslong investigation.

In the reports reviewed by CNBC, customers and physicians reported issues with syringes from manufacturers beyond those issued warning letters. Some found "foreign matter" in syringes, while others reported "multiple needles breaking off in the vials when drawing up vaccines," "medication delivering faster than it should," and "cracked" syringes. In one medical device report for Jiangsu Shenli Medical Production Co. Ltd, a customer reported that the syringe was causing "an inaccurate measurement of vaccine."

CNBC did not receive immediate responses from the three companies that received warning letters.

Irving, a major pharmaceutical manufacturer based in Texas, sources plastic syringes from Jiangsu Shenli Medical Production Co. Ltd. and Sol-Millennium Medical Inc., according to the FDA's medical device reporting database.

The FDA advised that U.S. suppliers, consumers, and health-care organizations should immediately stop using plastic syringes made by Jiangsu Caina Medical Co. Ltd and unauthorized plastic syringes made by Jiangsu Shenli Medical Production Co. Ltd unless absolutely necessary. The agency also stated that all other plastic syringes made in China should be used as needed until a transition to another product is possible, and urged users to monitor for defects.

McKesson did not immediately respond to a request for comment.

Besides Jiangsu Shenli Medical Production Co. Ltd and Sol-Millennium Medical Inc., there are other Chinese-based manufacturers that produce plastic syringes for McKesson, according to FDA data. Medical device reports also link Anhui Tiankang Medical Technology Co. Ltd., Jiangsu Caina Medical Co. Ltd., Suzhou Linhwa Medical Devices Co. Ltd., and Shanghai Kindly Enterprise Development Group Co. to McKesson.

Besides McKesson, other pharmaceutical giants, including Cardinal Health and Fresenius Medical Care, have faced issues with their syringes, resulting in class one recalls for incorrect dosages, therapy delays, pump malfunctions, and even syringe leakage and unknown black material inside the syringe.

The FDA stated that it believes there is enough supply and manufacturing capability for plastic syringes made outside of China, including in the U.S., to meet the shortage. Additionally, the agency will continue to assess issues with syringes manufactured in China.