TikTok’s Chinese parent company ByteDance is using H-1B guest worker visas to get some of its employees into the United States. Sen. Tom Cotton, R-Ark., has expressed concerns about who those employees are and whether they could help the Chinese Communist Party access sensitive user information.

“This threatens the safety and security of American citizens, and also functions as an avenue for the Chinese government to track the locations of and develop blackmail on Federal employees and contractors,” Cotton wrote in a letter to Department of Homeland Security Secretary Alejandro Mayorkas. 

Cotton wants DHS to provide a list of everyone who was sponsored by Tiktok and their job title. He pointed out in the letter that at least 300 TikTok employees are current or former employees of Chinese state-owned media. In 2022, the Department of Homeland Security approved 570 visas for employees to work at TikTok’s offices in California. Cotton described that as a “threat.”

TikTok has tried to address data concerns by saying all American users’ information is stored in the U.S. and its data centers are stored outside China. But multiple reports have indicated information is still accessible within China.

In October, Forbes reported that a team at TikTok planned to use the app to monitor the personal location of certain American citizens. The plan revolved around a Beijing-based team accessing the user information without their knowledge or consent. TikTok responded by saying it does collect some information to target advertisements based on location and to track inauthentic behavior. But Forbes said the documents they reviewed indicated the data collected was being used to surveil.

In June, Buzzfeed reported that leaked audio from internal company meetings showed ByteDance employees based in China repeatedly accessed non-public information from users in the United States.