The chief of a cab company implicated in a falsified smog check scandal said Friday that his firm and another company did not ask emissions testers to cheat on taxicab smog checks and had no incentive to do so.

"If I had knowledge of such a thing, I wouldn't allow it to happen," said Ray Chenoweth, president of Nellis Cab Co., who also was speaking on behalf of Desert Cab Co. The companies are among six taxicab companies cited Thursday by the Nevada Department of Motor Vehicles for falsified tests.

Chenoweth said such incidents with state agencies are frustrating.

"I didn't do anything," he said.

State officials allege a total of 118 taxis passed emissions tests actually taken by other cars, a scam called "cold piping." DMV spokesman Kevin Malone has said, "It almost had to be that someone at the cab companies had knowledge of it."

Malone stood by that statement Friday. "If they feel they didn't do anything wrong, we encourage them to take it to a hearing," he said. "They can put the evidence out there and let an administrative judge sort it out."

Those hearings are expected to start Aug. 1.

In a prepared statement, Nellis and Desert officials said, "We had no knowledge" that a contractor tasked to carry out smog checks "was failing to perform the smog checks on all vehicles that we sent to him for these required inspections. Upon learning about the contractor's violation of the state law and regulation, we took immediate steps to have the cabs in question smog checked."

Chenoweth did not name the contractor.

"So far, all of the cabs smog checked have passed their inspections. No greenhouse gases, no global warning, no problems," the statement read. "We will continue to do everything possible to remedy this situation quickly and work with state authorities to accomplish this."

The state's complaint alleges 45 Nellis cabs had smog tests that were rigged. That is more than one-third of the 130 full-time cabs the company is licensed to operate. Desert had 26 cabs cited out of 136 taxicab licenses.

Other cited companies are Western Cab Co., with 34 implicated cabs among 130 full-time taxicab licenses. And 13 cabs were cited among 531 full-time cab licenses belonging to Nevada Yellow Cab Co., Nevada Checker Cab Co. and Nevada Star Cab Co., all of which are owned by Yellow Checker Star Transportation Inc.

Implicated cabs are scheduled to have their registrations revoked by Friday, unless smog tests and registration applications are redone.

As part of the investigation, four emissions inspectors had their licenses revoked last month. Authorities have not publicly divulged the names of the company or companies they work for, citing an ongoing investigation.

Malone said some of the falsified tests, conducted between June of last year and January of this year, were caught in progress by state inspectors.

"One thing that did tip us off is that the investigators observed several cold piping smog checks going on," Malone said.

Chenoweth dismissed the suggestion that falsifying smog checks would benefit cab companies by allowing those cabs to remain on the streets and generate revenue.

"I have 40 cabs to use whenever the other cabs are down. When it comes time to smog a car, I take one of the standby cars" and put them into service, Chenoweth said. "I don't lose any money."

Chenoweth said he could not vouch for what happened to the cabs while in possession of the unnamed contractor during smog checks.

"When it comes to smoggings, we tell the guy, 'Here's the cars that are supposed to be smogged.' He takes the cars and brings them back," Chenoweth said.

Earlier, Yellow Checker Star operations manager Bill Shranko said that "there was no fraudulent intent" by his company, but he could not rule out that individual employees or contractors could have rigged smog tests.

Meanwhile, the state said it was possible that other emissions inspectors could be cited for involvement in the scam, though no other cab companies are expected to be implicated.

"We'll have to see where the investigation leads," Malone said. "It may lead somewhere, or it may not."