Health Secretary Robert F. Kennedy Jr.’s purge of tens of thousands of federal workers has halted efforts to collect data on everything from cancer rates in firefighters to mother-to-baby transmission of HIV and syphilis to outbreaks of drug-resistant gonorrhea to cases of carbon monoxide poisoning.

The cuts threaten to obscure the severity of pressing health threats and whether they’re getting better or worse, leaving officials clueless on how to respond. They could also make it difficult, if not impossible, to assess the impact of the administration’s spending and policies. Both outside experts and impacted employees argue the layoffs will cost the government more money in the long run by eliminating information on whether programs are effective or wasteful, and by allowing preventable problems to fester.

“Surveillance capabilities are crucial for identifying emerging health issues, directing resources efficiently, and evaluating the effectiveness of existing policies,” said Jerome Adams, who served as surgeon general in the first Trump’s administration. “Without robust data and surveillance systems, we cannot accurately assess whether we are truly making America healthier.”

The offices that ran the Sickle Cell Data Collection Program, the National Intimate Partner and Sexual Violence Survey, the Pregnancy Risk Assessment Monitoring System and the National Firefighter Registry for Cancer were scrapped. So were teams that reported how many abortions are performed nationwide, the levels of lead in childrens’ blood, alcohol-related deaths, asthma rates, exposures to radon and other dangerous chemicals, how many people with HIV are taking medication to suppress the virus, and how many people who use injectable drugs contract infectious diseases.