Sixty-eight members of Congress sent a joint letter to U.S. Department of Agriculture Secretary Tom Vilsack on Monday, asking that he withdraw an agency proposal that would substantially change how chickens and turkeys are inspected and processed in poultry plants across America.

In the four-page letter, lawmakers said they were worried that the proposed system would “undermine” the agency’s “food safety and humane slaughter practices” due, in part, to provisions that would replace 40 percent of government inspectors with plant employees while also allowing plants to speed up processing lines by up to 25 percent.

The group of U.S. representatives said the processing line increases would likely compromise the safety of workers, who already suffer from high rates of carpal tunnel syndrome. The letter also cited an Oct. 29 Washington Post article that detailed problems with animal cruelty with current line speeds, which could be exacerbated under the new proposal.

The USDA has said it believes salmonella rates will fall by 1.9 percent under the new system, but the lawmakers pointed to a Government Accountability Office report that raised serious questions about this claim.

“While we strongly support modernizing our food safety system and making it more efficient, modernization should not occur at the expense of public health, worker safety, or animal welfare,” the members, led by Reps. Rosa DeLauro (D-Conn.), Jim Moran (D-Va.), Louise Slaughter (D-N.Y.) and Bennie Thompson (D-Miss.), wrote to Vilsack. “We therefore harbor serious concerns over what we believe are the Food Safety Inspection Service (FSIS)’s inadequate considerations to date of these issues in promulgating this rule…We urge FSIS to withdraw the proposed rule until the agency has thoroughly addressed its impact on the public, workers, and animals and adherence to good commercial practices.”

The letter was signed by 67 Democrats and one Republican — Michael G. Fitzpatrick, of Pennsylvania.

USDA officials said they have previously received six letters from members of Congress about the new inspection system since it was first proposed in early 2012. According to the agency, four letters were against the proposal – one with four signatures and three others with one signature. One letter was in favor of the proposal with 13 signatures while another was neutral with two signatures.

Earlier this month, more than 100 farm, food safety, worker rights, animal welfare and environmental groups sent a joint letter to the White House, asking President Obama to reject the proposal.

According to several food and worker safety groups, Vilsack has said in recent meetings that he hopes to finalize the proposed inspection rule as soon as next month. The USDA’s regulatory agenda for this year showed the agency hoped to finalize it in April.