Often, i've found, you do something in business for one reason and only later discover that your decision has had ramifications you never imagined. With luck, they'll be good ones. That's been my experience with drug testing, which I began doing somewhat reluctantly about six years ago.

I knew we had a problem in our warehouse at the time. We'd heard rumors about marijuana being bought and sold on our premises. We'd also seen a marked increase in petty theft and minor accidents, which I suspected was related to drug use. People were running forklift trucks into walls and dropping skids of boxes onto the floor as they were being moved from one spot to another. Items would disappear from the shipments of goods that we kept in the warehouse for customers of our trucking business. I couldn't blame all of the problems on drug use, but I felt certain that it was a contributing factor.

Still, I hesitated to start drug testing. Part of my reluctance, I suppose, was a subconscious fear of feeling hypocritical. Like other members of my generation, I'd tried marijuana in my youth, and I'd be lying if I said I didn't inhale. When the testing issue arose, I had reservations about punishing people for doing something I'd also done at their age. In addition, I knew that drug testing could result in our having to let some employees go -- maybe even some good, long-term employees -- at a time when the growing labor shortage was making hiring increasingly difficult. That seemed likely to cost us a substantial amount of time and money -- not to mention emotional anguish -- over and above the cost of the testing itself. But I eventually decided that we had to go forward anyway, mainly because of the accidents. No one had been seriously injured, but I knew our luck would run out sooner or later.

So, after consulting with some experts we'd brought in to help us, we announced our new policy. Henceforward we would test all job applicants for use of illegal drugs and hire only those whose results came back negative. As for our current employees, we wanted to give people using drugs a chance to clean themselves up. Marijuana, we explained, would show up in urine samples for at least a month after use. Other drugs passed through the body's system more quickly. Accordingly, we would wait 45 to 60 days before beginning testing. Thereafter we would test everyone in the company, including me, my wife, my daughter, the other executives -- everyone.

The tests would be random and would not be announced in advance. People who tested positive for drugs other than marijuana would be terminated immediately. Those who tested positive for marijuana use only would be given a second chance. After another 45-day waiting period, we'd do a second round of tests. Employees who failed both tests would be let go.

Despite the warning, we were in for a shock. In the first few days of testing, half of the samples from current employees came back positive. You can imagine how we felt about the prospect of replacing 50% of our 130-person work force. We decided to slow down the testing, so that we'd have time to find the new people we'd need.

I had hopes for the employees who flunked the first test. Before the second round began, I asked several people if they were ready. Everybody said, "Oh, yeah, I'm clean." In the end, though, only one of them passed the second test, a young man named Bruce Howard. Although we offered the others drug treatment and a chance to reapply for a job, we got no takers. Overall, we wound up losing about 25% of our work force -- fewer than we'd feared, but a significant number nonetheless.

Yet the drug testing did work. The accident rate declined, as did the incidence of petty theft. Even more gratifying was the response of the employees who remained: They thanked us. They said they felt safer. Only then did I begin to appreciate the real importance of having a drug-free company. It wasn't just about reducing our liability, or even keeping someone from getting hurt, as much as we wanted to do both. It was also about creating a better working environment for the other employees, the ones on whom we depend most heavily, the people we absolutely must figure out how to keep.

And on top of that, we got a bonus. Our drug-testing program made us more attractive to insurers, allowing us to move our policies to a better provider. Over time, moreover, a lower accident rate would translate into lower workers' comp costs.

These days, more than 75% of our new hires flunk the drug test, a result I find disturbing.

Since then, we've continued to do random drug testing inside the company, in addition to testing all of our new hires. More than 75% of the latter group flunk the test, a result I find disturbing. I like to think that we're offering people an opportunity to have a better life, and it's extremely disappointing when they turn down the opportunity.

Consider the case of an intelligent, well-spoken, clean-cut young woman we wanted to hire as our executive secretary. She'd come to us through a reputable employment agency that had checked out all of her references. She had a great resume, and she impressed everyone in our company who spent time with her. I was the last person to interview her, and she impressed me, as well. In the course of our discussion, I mentioned that we drug test all new hires. She didn't bat an eye. Mainly she wanted to know the length of her lunch break. I told her it was 45 minutes. "Good," she said. "I need that time for myself."

"No problem," I said.

The next day we called the agency and said we intended to hire her. Someone from the agency called her with the news. She was thrilled. "They'll do the drug test tomorrow," the agent said.

There was a brief silence on the other end of the line. "They really do drug tests?" the job candidate asked. "That could be a problem."

"Why?" asked the agent.

"Because I won't pass," the young woman said. She explained that she was addicted to crack cocaine. She smoked it every day at lunch. That's why she needed the time for herself. The agent was stunned, and so were we when we were told why our new executive secretary wouldn't be showing up for work. "What a waste," I thought. "What an awful waste."

Understand, I'm not judging the morality of recreational drug use here. I generally believe that what people do on their own time is their own business. Nor do I mean to suggest that every marijuana smoker or cocaine user is a thief, a safety risk, or a malingerer. Some people can, in fact, function under the influence of drugs. Our would-be executive secretary had glowing references.

I know, however, that someone who smokes crack at lunch or marijuana after hours is not able to give the company her or his best efforts at work, and that's what I ask of employees. I want them to do their best while we're paying them. In return, I'll do everything I can to make sure that their jobs are secure and that they have a good work environment.

But there's another side to the drug-testing story that I didn't see until recently. The person who opened my eyes was Bruce Howard, the only employee who'd flunked the first drug test and passed the second. Since then, Bruce has advanced steadily in the company. He's now one of our top supervisors, with a whole department reporting to him. A few months ago, my wife, Elaine, and I took all eight of the supervisors out to lunch to thank them for their contributions. We handed out bonus checks and talked about the importance of their role and the difference they'd made at CitiStorage. Elaine then asked if anybody had anything to add.

Bruce stood up. He said, "I love it here, but I want to tell you I'm one of those who almost didn't make it." His first stint at the company hadn't lasted long. He'd been fired for absenteeism and poor performance. A few years later we hired him back, hoping he'd matured. Everything seemed to be going well until we started our drug-testing program and he failed the first test. "I came to a crossroads," Bruce said. "My job and my new life were important to me, but I realized I couldn't hold on to them unless I made a choice. Back then, I hung out with guys who smoked weed all the time. I knew that if I kept doing that, it would be too hard to quit. So I had to find new friends. I had to switch places I went to. I had to change all my routines. With the help of my fiancee, I did it. I changed my whole life. I became a more focused and serious person because, you know, you get rid of the distortion that comes from smoking weed. And I've never regretted making that choice. My life is better now in every way."

Never did I imagine when I started the drug-testing program that I might actually be tossing a lifeline to someone, but it sure makes me feel good to know I did.

Norm Brodsky is a veteran entrepreneur whose six businesses include a three-time Inc. 500 company. His co-author is editor-at-large Bo Burlingham.