do’s and don’ts for employers

Testing employees for drug/substance use is by no means a straightforward legal area, as there are labor law and data protection implications that should be considered by employers wishing to do it.

The starting point is that an employer should only perform drug testing on employees where it is justified, necessary and a proportionate means of achieving a legitimate aim. The typical example of where this might be the case is where there are health and safety considerations, for example where employees are required to drive vehicles or machinery, or where the role in question involves taking caring for vulnerable people or children.

Although there may be other situations where drug testing at work might be warranted, for example where working under the influence of drugs could cause serious damage to the employer’s business, there is little Drug testing of workers is likely to be warranted, unless it is for health and safety reasons.

An employee’s written consent must always be obtained prior to any drug testing. The reasoning and modalities of the tests should also be discussed with the employee.

Dealing with substance abuse in the workplace is also likely to have data protection implications. For example, holding drug test results would constitute processing of personal data under UK data protection law. The results of any drug test would also constitute special category personal data relating to an employee’s health, and any processing of such data would therefore be subject to stricter data processing rules than those generally applicable to other types of personal data.

The Information Commissioner’s Office (ICO) has published a Data Protection Code on Obtaining and Processing Employee Health Data, which sets out the following drug testing guidelines:

  • Only use drug tests if they provide significantly better evidence of impairment than other less intrusive means.

  • Employers must be transparent with employees regarding the drugs/substances they are being tested for.

  • Any decision to test employees must be based on reliable scientific evidence regarding the effect of the substances in question. Testing should also be limited to substances and the extent of exposure that will meet the purposes for which testing is being done.

  • Random testing should be just that.

  • Do not test all workers if only workers performing a particular activity are at risk. Even if testing all workers is “random”, testing all workers will rarely be warranted.

  • Testing in response to a specific incident where there is a reasonable suspicion of drug abuse is more likely to be warranted than random testing.

To summarize…


  • Consider carefully whether drug testing is justified, proportionate and a necessary means to achieve a legitimate aim, noting that it will only be justified if it is for health and safety reasons.

  • Consider having a substance abuse policy in place to clearly outline the rationale and terms of any testing, if you believe testing might be warranted.

  • Obtain employee consent before performing a drug test.

  • Treat filter results as “special category” personal data and consider appropriate data protection provisions.


  • Implement a “mass testing” policy.

  • Tell employees that the tests are “random” if not.

  • Let’s assume that the mere fact that you have a health and safety reason for having a test is justified, proportionate and necessary.

Ross Meadows is a partner and head of employment at Oury Clark Solicitors

Previous Tert-Butanol Market – Driving Transformation 2027 – Travel Adventure Cinema
Next Odin's Smoke Shop Search Reveals Illegal Drugs, Guns, Says BINTF – Chico Enterprise-Record