Almost all of the 20 U.S. state government-run health insurance marketplaces shared residents’ application information with advertising and tech giants, including Google, LinkedIn, Meta, and Snap, according to a new investigation by Bloomberg.

The report drives home the privacy problems created by pixel-sized trackers, which allow website owners to collect information about their visitors, often for web analytics and identifying bugs. A common tool in digital advertising, these trackers also allow the collection of personal information if misconfigured and placed on websites that contain sensitive content, such as healthcare data.

Per Bloomberg, New York’s health insurance exchange shared information with several tech companies about a person’s application, including whether they provided details about whether they have incarcerated family members.

The health insurance exchange for Washington, D.C. also asked residents about the person’s sex and race, which TikTok’s pixel tracker attempted to redact. Some races were masked and others were not, the publication reported. A spokesperson for the Washington, D.C. exchange told Bloomberg that residents’ email address, phone number, and country identifiers were also shared with TikTok.

Washington, D.C. paused its rollout of the TikTok tracker, and Virginia removed the Meta tracker from its website after Bloomberg found it was sharing residents’ ZIP codes with the tech giant.

This is not a new problem, and has previously caught out telehealth startups and healthcare giants alike. Several companies and healthcare giants have had to notify millions that they inadvertently collected and shared their health information with tech giants, whose profits are derived from using consumer data for advertising.

But Bloomberg’s investigation shows that these pixel trackers can affect large swathes of the population when placed on government websites. The publication noted that more than seven million Americans purchased health insurance for this year through a state health insurance exchange.