The U.S. Chamber of Commerce and conservative groups are lobbying lawmakers to give companies legal immunity if front-line workers believe they got sick on the job, or if families say their loved one died after catching COVID-19 at work.

Lawsuits from workers who were exposed to COVID-19 are “perhaps the largest area of concern for the overall business community” ahead of the economy reopening, a chamber memo to its members this week states.

The powerful lobby argues the sheer number of lawsuits could overwhelm businesses.

Businesses say they keep their workplaces safe, but the memo indicates that major corporations privately acknowledge that many so-called essential employees will get sick or die.

Conservative groups including Americans for Prosperity, the nonprofit founded with funding from businessmen Charles and David Koch, made a similar appeal to members of Congress in a letter this week.