Random Drug and Alcohol Testing

Many UK construction sites operate random drug and alcohol testing as part of their fitness for work policy.
Testing is typically carried out by an independent occupational health provider using oral fluid or urine samples.
A positive test result usually leads to immediate removal from site and disciplinary action by the employer.
The Transport and Works Act 1992 makes it a criminal offence to be unfit through drugs or alcohol at work.
Cannabis can remain detectable in the body for up to 30 days after a single use depending on the test type.
Prescription medications that cause drowsiness must be declared to your supervisor before starting work.
The legal alcohol limit for driving does not apply to construction — most sites have a zero tolerance policy.
Random means anyone can be selected at any time — there is no way to predict when you will be tested.
Refusing to take a test is treated the same as a positive result on most UK construction sites.
For-cause testing can also be triggered by an accident, near miss, or observed signs of impairment.

Site safety	A worker impaired by drugs or alcohol has slower reactions, impaired judgement, and puts every colleague at risk.
Zero tolerance	Most principal contractors operate zero tolerance — a positive result means immediate removal from site and likely dismissal.
Legal consequences	Causing an accident while under the influence can result in criminal prosecution and personal injury claims.
Prescription duty	Even legal medications can impair your ability to work safely — declaring them protects you and your colleagues.

Do

Don't

Arrive at work every day completely free from the effects of alcohol and drugs.
Declare any prescription medication that may cause drowsiness to your supervisor.
Read your employer's drug and alcohol policy and understand the consequences fully.
Cooperate with any random or for-cause test when selected on site.
Allow sufficient time after drinking alcohol for it to clear your system entirely.
Seek confidential support from your GP or employee assistance programme if struggling.
Report a colleague you believe is impaired to your supervisor — it may save lives.
Know that energy drinks and some cold remedies can affect alertness and test results.
Inform the testing provider of any legitimate prescription medications before the test.
Support colleagues who seek help for substance issues — recovery is possible.

DON'T attend site under the influence of alcohol, drugs, or impairing substances.
DON'T assume last night's drinking has cleared by the morning start time.
DON'T use recreational drugs at any time if you work on construction sites.
DON'T refuse a random test — refusal is treated as a positive result on most sites.
DON'T take prescription medication that impairs you without informing your supervisor.
DON'T drive to site if you are over the legal alcohol limit or impaired by drugs.
DON'T cover for a colleague you suspect is impaired — report it confidentially.
DON'T assume herbal or legal high products are safe or undetectable in testing.
DON'T ignore the warning signs of dependency in yourself or your workmates.
DON'T risk your career, your licence, and your family for a substance you can avoid.

See also: Drug and Alcohol Awareness | Fatigue Management and Working Hours

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