Private employers, with increasing frequency, are adopting programs to test workers for drug use. An article by Ruth Marcus and Margaret Engel published in this paper Sunday described policies implemented by a number of companies to deal with the growing presence of drugs in the work place. Simple, relatively inexpensive and accurate tests are now available that will detect the presence of any number of drugs in a urine sample. Employers concerned about the physical condition of workers on the job and the absenteeism and medical costs of drug use at any time are requiring these tests of job applicants and current employees.

Most people may agree that employers have a responsibility to protect the public and co-workers from those who get high on the job. We don't want railroad engineers, pilots or armed security guards to be less than completely alert at all times. Nor should the safety of those who work in factories or on construction sites be jeopardized by a colleague who's on drugs. Even when safety is not an issue, an employer has a right to expect accuracy, efficiency and a full day's work from those he has hired, and drug users often fall short of that standard. Employees who appear to be addicted to any substance -- legal or illegal -- that impairs performance should be subject to challenge.

Random, sweeping tests of all employees for signs of drug use are another matter, however, even though these chemical tests are far more accurate than so-called lie detectors. Where safety is not a concern, compulsory testing may be deeply resented by employees who give no sign of addiction. The employer has a legitimate interest in screening out less efficient and law-breaking drug users, and may be legally entitled to require periodic urinalysis as a condition of contnued employment. But inflexible policies can have side effects -- low morale, labor grievances and litigation -- that are costly too.

Enlightened companies will strive to diminish these by moving gradually and making the process fair. Allowing workers to take a second series of tests, for example, makes sense. So do counseling and treatment programs as a first step. A promise of confidentiality will also reduce resentment and encourage cooperation. When technology moves rapidly, as it has in the case of testing for drugs, it is usually wise to slow down and consider its implications before rushing ahead.