Officials at the Health and Human Services Department have proposed limiting telework to one day per week, and potentially eliminating the practice altogether, according to a union representing department employees.

The National Treasury Employees Union and HHS are in the final week of negotiations as mandated by the Federal Service Impasse Panel, which asserted jurisdiction over the collective bargaining process last month, over the union’s objections. After parties reach a Saturday deadline, they will submit their final offers and justifications to the panel, which will impose a new contract.

The new HHS proposal would limit employees access to telework—which currently lacks a cap—to one day per week. And it allows the department to cancel unilaterally any scheduled telework day for nearly any reason and without notice and require an employee to come into the office.

“[The] employer reserves the right to require more frequent days at the official worksite and duty station and to recall employees without prior notification from scheduled telework days for situations deemed appropriate by the employer, either planned or unplanned, including, but not limited to, office assignments, meetings, absence of other employees, emergency situations, training classes, business reasons, operational demands, or mission related needs,” the proposal states. “[Furthermore], in such instances the telework day is forfeited and the employee is not entitled to substitute another telework day.”

HHS’ initial proposal would have gone even farther, but negotiators stripped language at NTEU’s request that would have barred employees from telework if they were absent on another day of the week for any reason, including official holidays.

NTEU National President Tony Reardon blasted the proposal and suggested it could lead to a mass exodus from the agency.

“Telework is a smart, cost-effective workplace policy that has been shown to increase productivity, cut administrative and real estate costs, and reduce traffic congestion,” he said. “Arbitrarily eliminating telework would have a devastating impact on current workers, and likely risks skilled workers running for the exists and turning down job offers, and will certainly make the U.S. government an outdated employer.”

HHS did not immediately respond to a request for comment.

The negotiations have drawn the attention of Sen. Kamala Harris, D-Calif., who penned a letter to HHS Secretary Alex Azar Thursday urging the department to reverse course in its negotiations. HHS has been accused by lawmakers and union officials of bargaining in bad faith with NTEU, engaging in “surface level” bargaining without a desire to reach agreement in order to “check boxes” in the process to reach the impasse panel, which is entirely made up of Trump administration appointees.

“Because the two parties have not reached a true impasse, I urge HHS to bargain in good faith with NTEU to resolve these disagreements,” Harris wrote. “HHS’ actions throughout this process fit the administration’s disturbing pattern of hostility toward federal employees and the labor organizations that represent them.”

HHS is the latest in a string of federal agencies to move to significantly curb the use of telework, despite a report from the Office of Personnel Management that it is a valuable tool that saves money and improves employee performance and morale. The Education and Agriculture departments both controversially cut telework to one day per week earlier this year.