The cleanup of coal tar at the old Geneva Steel Mill is on hold, as Utah Department of Environmental Quality is giving the current owners time to regroup after neighbors complained about the nauseating smell.

Utah DEQ asked U.S. Steel on Friday to stop work on cleaning the coal tar pits until after the holidays, DEQ spokesman Jared Mendenhall said, and the company agreed.

DEQ received the first complaints of an odor coming from the Geneva site on Nov. 8. Residents in housing developments in nearby Lindon, Vineyard and Orem had complained the odor was causing nausea.

DEQ’s Division of Waste Management and Radiation Control ordered U.S. Steel to stop its remediation efforts the week of Nov. 11, while state experts tested the air. Operations restarted on Dec. 10.

The odor was identified as naphthalene, the active ingredient in mothballs. The petrochemical benzene was also being emitted.

Workers at the coal tar pits wore air-monitoring badges, which showed levels of the chemicals were below the permissible exposure level, according to Occupational Health and Safety Administration (OSHA) regulations, DEQ reported.

“Just because it hasn’t reached that level doesn’t mean it isn’t affecting people,” Mendenhall said.

Since the cleanup relaunched on Dec. 10, U.S. Steel has been working on ways to reduce the odor and its impact on the neighboring residents. “They are trying to be good neighbors,” Mendenhall said.

The Friday stoppage would not have had a huge effect on the cleanup. According to a Dec. 11 update by DEQ, U.S. Steel was scheduled to stop work after Sunday for the Christmas and New Year’s holidays. Work was to resume on Jan. 3, and Mendenhall said that timeline generally remains in effect.

The coal tar is a byproduct of steelmaking, a greasy residue from the heating of coal to create coke. The Geneva mill opened in December 1944, to boost American steel output during World War II, and closed in 2001. The old blast furnaces were demolished in 2005, and a master-planned community was announced for the site in 2017.