"In the 10 years that I've raced, I've never been drug-tested," Harvick said. "To me, that's not a proper drug policy for a professional sport. We haven't made any headway whatsoever on the drug-testing policy."
Harvick and Stewart were reacting to an ESPN The Magazine story this week in which former driver Aaron Fike said he competed in Craftsman Truck Series races while he was on heroin.
"I have been in a race with him and I know for a fact that he's not the only one," Harvick said. "There's another driver that was suspended that I can almost guarantee you was in the race car while he was under the influence, and that pisses me off.
"I'm sure I'll be blasted for saying what I feel, but I don't want to be on a race track with people like that. It's irresponsible more than anything."
All four Cup drivers said they are in favor of regular testing.
"I would love it,'' Stewart said. "I've never been asked to take one yet. I think it should be mandatory to have random drug testing. I think it's a great idea. The Fike situation shows that as an organization, we're not doing a good job of seeing this before it happens."
NASCAR's substance-abuse policy includes the right to test any driver at any time, but officials only do so if they believe a competitor might have a problem.
"The responsibility here rests across the board -- with the drivers and competitors, owners, teams and NASCAR," said Kerry Tharp, NASCAR's director of communication. "We test an individual when we have reasonable suspicion. A positive test results in severe consequences and is a career-changing moment for that person.
"NASCAR's policy is also supported by the various policies that the teams have in place that are required under the driver/owner agreements. No system is flawless, but we believe our zero tolerant policy that is in place has served the sport well."
Fike was arrested last year in Ohio for possession of heroin.
"I had a long talk with NASCAR about this last year,"
Harvick said. "It almost seems like it fell on deaf ears. They were more mad that I had a reaction to the situation than they were about trying to move forward.
"They heard what I said, but my name's not Jeff Gordon. I'm disappointed that we have to react and answer all these questions again."
Tharp said NASCAR officials always take it seriously when drivers come to them with questions or complaints.
"Let me assure you that no issue or conversation that we have with a driver, owner or team member ever falls on deaf ears," Tharp said. "Now, they might not always come out of the meeting with the answer they're looking for, but we listen."
Harvick wants to see NASCAR test drivers and crew members several times a year.
"I'm sure I'll have to do it for speaking my mind,"
Harvick said. "But if I have to pee in a cup 15 times a year, I'm happy to do it.
"The bad part is it isn't fair to the 95 percent of his garage that is clean. But I want everybody in the world to know our sport is clean. I want fans and sponsors to know this garage is clean."
Harvick and his wife, DeLana, own truck series and Nationwide Series teams at Kevin Harvick Inc. Harvick does not conduct drug tests for his employees.
"I don't right now and maybe we need to change the way we look at it, too," he said. "But in the end, it's the responsibility of [NASCAR] to make sure all the drivers are clean."
Harvick said Fike drove a couple of races for KHI several years ago.
"There was no reason to think something was wrong,"
Harvick said. "I don't know about drugs, to tell you the truth. But I want to know about the guy racing next to me and not have to wonder if he was out the night before and isn't clean."
Kahne said he had suspicions about Fike.
"I definitely wondered about Aaron, so I'm sure others did," Kahne said. "When he said he did heroin before a race, that's incredible that no one knew. As much money as there is in this sport, I think we should take a little more effort to make sure every driver is clean."
Harvick believes NASCAR should have changed its substance-abuse policy long ago.
"You can tell I'm a little bit frustrated about the situation," he said. "As someone who respects the sport and respects my sponsors, I'm upset that I have to answer questions about Aaron Fike. It really ticks me off, because every driver in this garage should be taking random drug tests."
Johnson, who has won the last two Cup championships, said he was shocked to learn about Fike's admission.
"I cannot believe it,'' Johnson said. "It's absurd. I don't know where things go from here. I've not been testing, but I'm confident every driver is willing to do whatever NASCAR decides to do."
Harvick believes NASCAR needs to do a better job of staying ahead of the curve.
"It's just like the safety thing back in 2001," he said. "We didn't react until that situation happened [with Dale Earnhardt's death]. With drug-testing, there's no reason in the world today not to be proactive.
"This is about forward thinking about how the drivers are perceived from a public standpoint. If I'm a fan, I don't want to think, 'Are they really clean?' This always has been perceived as a clean sport. Let's not let that change now, because it is. But let's prove it."
Terry Blount covers motorsports for ESPN.com. He can be reached at email@example.com.