U.S. Sen. Michael Bennet and 16 other senators signed on to a letter last week requesting that the U.S. Census Bureau describe its plans to Congress for ensuring the health and safety of census takers during a potential coronavirus outbreak.

“The Census Bureau must be prepared to provide guidance to census takers on appropriate health and safety precautions while conducting the census,” the senators wrote. “The Census Bureau may also need to prepare for challenges in recruitment and retention of census takers in the event of coronavirus outbreaks.”

The letter also raised the possibility that the virus could lower response rates, but did not elaborate on why that might be the case.

Between March 12-20, 95% of households in the country will receive a notice to fill out the census form online or by telephone. There will be a reminder mailed shortly afterward, and a paper questionnaire will go out to households in mid-April that still have not responded.

Only as a last resort will census takers visit a home to get a response in person.

Terri Ann Lowenthal, who formerly worked for the U.S. House of Representatives’ census oversight subcommittee, told Quartz that among the many uses of census information is its role in developing government response plans to disasters.

“Census data are central to emergency planning and preparedness and disaster response and recovery, including responses to public health crises and recovery,” she said. “This particular emerging health crisis is another reason why an accurate census is so important.”