Thirty Utah businesses called on Gov. Gary Herbert on Tuesday to improve air quality by adding new curbs on wood smoke and vehicle emissions to the state’s latest plan for cutting pollution.

Heavyweights such as Zions Bank and Mark Miller car dealerships joined with outdoor clothing giant Patagonia, Ancestry.com and an assortment of other retailers, restaurants, real estate firms who also signed a letter to Herbert, urging him to step up on the issue.

 "As leaders of Utah's business community,” they wrote in a jointly signed, five-page letter, ”as entrepreneurs and employers, we call upon you to propose these bold strategies for addressing air pollution in Utah."

Their joint appearance Tuesday afternoon came as state regulators are saying they are likely to miss a December deadline from the Environmental Protection Agency for Utah’s latest plan to cut small particulate pollution, the sooty gunk that builds up in the winter under the Wasatch Front’s inversions.

(Steve Griffin | The Salt Lake Tribune) Afternoon haze in Salt Lake City on Tuesday August 29, 2017. A group of Utah business is urging Gov. Gary Herbert and state lawmakers to take more aggressive action on air quality.

That deadline, in turn, stemmed from the state’s failure to meet a 2015 deadline for compliance with federal air quality standards.

Nazz Kurth, president of Petzl America, the Utah-based arm of the international manufacturer of professional climbing gear, on Tuesday called that delayed progress on Utah’s pollution-combating plan “weak.”

“Why? It’s about political will and priorities,” Kurth said. “This is a mission-critical issue.”

Requests to Herbert’s office for comment on Tuesday went unanswered, but state regulators may consider steps similar to some of the letter’s recommendations.

Business leaders said the state pollution plan to the EPA “offers and incredibly important opportunity” to “reduce emissions while ensuring our communities and businesses thrive."

Standing with other private-sector leaders, Kurth said the state’s poor air quality has prevented his business from recruiting employees with specialized talent to Utah. He recalled several episodes of being midway through a job interview, only to have the prospect turn down an offer due to the region’s poor air conditions.

(Steve Griffin | The Salt Lake Tribune) Haze over Rice-Eccles Stadium in Salt Lake City Tuesday August 29, 2017. A group of Utah business is urging Gov. Gary Herbert and state lawmakers to take more aggressive action on air quality.

Several business owners mentioned their own pollution-reduction steps, such as installing solar panels and electric-vehicle charges in their workplaces, and encouraging employees to use mass transit or telecommute.

Utah businesses have contributed to improving the air, said Erin Strahm, program administrator for nonprofit Leaders for Clean Air, which helps businesses find ways to cut their impact on the airshed. It’s time, Strahm said, for the state leaders to take the effort seriously.

“We all want clean air — we’re asking for clean air,” she said. “Why isn’t our representation?”

Kelly Lake, founder of LUX Catering and Events, said she believes Utahns have become complacent about poor air quality days. “We’ve come to expect this,” she said, “and frankly I think it’s time to expect more.”

Bryce Bird, director of the Utah Division of Air Quality, has said state air regulators have not ruled out some of the actions requested by business leaders’, including increased regulation of wood smoke. But truly innovative air quality solutions that hold promise for Utah, Bird said, are difficult to come by.

Bird said the state’s air quality plan — due to the EPA by Dec. 31 — has been delayed because DEQ staff is still working out technical details and computer modeling.

Rich Mylott, a spokesman for EPA Region 8, said that if Utah does not submit a plan within six months of Dec. 31, 2017, the Clean Air Act requires the EPA to begin drafting a plan on Utah’s behalf.