WebMD has published an article about the SAMHSA report Worker Substance Use and Workplace Policies and Programs.

Some of the facts highlighted in the article include:

The report concludes that nearly 11 million American workers abuse or are dependent on alcohol, while another 3 million abuse illegal drugs. The figures represent more than 8% of the total full-time workforce, though some industries have far more substance abuse.

The food service and construction industries had among the highest levels of drug and alcohol use across the economy. Nearly one in five construction workers admitted drinking heavily in the past month, the report found.

About four in 10 workers work for employers that require drug or alcohol testing during the hiring process. Those workplaces also tend to have fewer drug users on the payroll. But researchers still don’t know if the tests are actually weeding out substance abusers.

They also showed workers who acknowledge drinking heavily are more likely to miss work or frequently change jobs. Nearly 14% of workers who reported drinking heavily in the past month said they’d also skipped one or more days of work during that time. Just more than 8% of nondrinking workers said they’d skipped work.

Drug detection times in urine are expressed below in terms of lower and upper boundaries. The amount of time that a drug / metabolite remains detectable in urine can vary, depending on the following factors:

• Amount and Frequency of Use: Single, isolated, small doses are generally detectable at the lower boundary. Chronic and long-term use typically result in detection periods near or at the upper boundary.
• Metabolic Rate: Individuals with slower body metabolism are prone to longer drug detection periods.
• Body Mass: In general, human metabolism slows with increased body mass, resulting in longer drug detection periods. In addition, THC (marijuana's active ingredient) and PCP are known to accumulate in fatty lipid tissue. Chronic users, physically inactive users, and individuals with a high percentage of body fat in relation to total body mass are prone to longer drug detection periods for THC and PCP.
• Age: In general, human metabolism slows with age, resulting in longer drug detection periods.
• Drug Tolerance: Users typically metabolize a drug faster once a tolerance to the drug is established.
• Urine pH: Urine pH can impact drug detection periods. Typically, highly acidic urine results in shorter drug detection periods.

Note: In a small percentage of cases, users may test positive longer than times shown - most notably in cases of long-term chronic abuse, in individuals with significant body mass and/or body fat, and in individuals with health related issues resulting in abnormally slow body metabolism.

Q: Can you help? I get my driving licence back next month after a 2-year ban for drink/driving. I no longer drink but I do smoke Marijuana occasionally. I have to be blood tested by a doctor before I finally receive my licence - do you know if they also test for Marijuana and if so would this invalidate my application. I guess what I'm trying to ask is, how long does Marijuana stay in the blood?

A: Marijuana can be detected in blood samples for around few days to a month, depending on what they are looking for (pure drug or metabolites), the sensitivity of the test, how long ago you last used, and how much and for how long you were using.

If your licence is refused on the basis of a positive test for cannabinoids, this should be readily challenged in the courts. There is no evidence that Marijuana causes any significant impairment in driving or risk to road safety (except when used with alcohol), and indeed much evidence suggests that it may contribute to safer driving behaviour, particularly among young men otherwise more prone to driving aggressively.