Cycler, I think we been down this path before. As there are pro's and con's to Urnie testing that I have pointed out before.
As in the State Law and Rules, the burden of proof needs to be meet for a Denial.
From the Labs;
Studies indicate that marijuana and alcohol potentate one another more than either drug alone. Thus, smaller amounts of ethanol and marijuana may increase toxic effects. Peak levels of marijuana metabolites in the urine occur about five hours post dose and thus are not useful in predicting the degree of intoxication. Urinary presence only indicates recent exposure. Note marijuana metabolite testing is available only in urine, not hair.
The initial screening cutoff level is 50 ng/ml. The GC/MS cutoff level is 15 ng/ml. The elimination half-life of marijuana ranges from 14-38 hours. At the initial cutoff of 50 ng/ml, the daily user will remain positive for perhaps 7 to 30 days after cessation. At the confirmation level of 15 ng/ml, the frequent user will be positive for perhaps as long as 15 weeks. Marijuana metabolites' storage and slow release from lipid tissues is the reason for this long detection period.
http://healthy.net/scr/article.asp?Id=8085
But, lets not forget, a smart employee, if he/she knew their Rights pertaining to any Drug Test, can legally dispute such test, and win with ease, if they knew their rights under the given Law. Hence, the fact, the work comp claim could simply come back to life.
Please remember, no employer wishes an employee to be too smart about legal employee rights...
Any employee can first request the following information before taking a Drug test;
What is the name and address of the lab that will perform the test ?
EXACTY what test or tests are to be used ?
For each test performed, list the type and quantity of specimens required ?
For each test performed, list the percentages for false positive and false negative results.
Provide statistical justification for these percentages.
In the case of a false positive, what are the established procedures for retesting ?
How many times will retesting be permitted ?
What is the established procedures for resolving consistant false positive results ?
What facility is going to extract the specimen(s) ?
How much of each type of specimen is going to be extracted ?
Are the lab and the blood extraction facility bonded ?
What company carries their malpractice insurance and what are their policy numbers ?
EXACTLY what information will be release from the lab to the employer ?
It is required that all results be forwarded to me.
Unfortunately, this may be difficult since urine tests may detect marijuana 1-5 days after an occasional use, 1-3 weeks in regular users, and 4-6 weeks in multiple daily users. Since urine tests do not detect the psychoactive ingredient of marijuana, THC, but rather other, nonactive metabolites, they in no way measure impairment;
Although urine tests are far from infallible, it is difficult to challenge positive test results. "False positives," in which workers are wrongfully accused of marijuana use, are highly unlikely so long as labs exercise proper care (however, not all labs do this). The standard procedure is to first screen the samples with an immunoassay test (e.g., EMIT® or RIA®), then confirm positive results with the more accurate gas chromatograph mass spectrometer (GCMS). This virtually eliminates the chance of false positives in exchange for a relatively high rate of "false negatives," where drug use is not detected. The sensitivity of the test is determined by the concentration of metabolites it is set to detect: for the Dept. of Transportation, the standard cutoff is 50 nanograms/milliliter (ng/ml).
LEGAL CHALLENGES: Prospective employees have no legal right to challenge pre-employment drug screens. However, workers who are already employed may be able to challenge their employers' drug testing plans in certain situations depending on labor law and local regulations. Avoid signing anything that gives your boss the right to arbitrarily test you; by stating your objections, you will strengthen your right to refuse a test. If you think you are being unjustly tested, you may have cause for legal action. San Francisco, Berkeley and some other jurisdictions forbid on-the-job drug testing except in safety-sensitive positions.
The employer to pay worker's compensation unless the employee's accident was caused by intoxication. A positive drug screening may show the presence of an intoxicant, but does not necessarily demonstrate that an employee was 1) intoxicated at the time of the accident or 2) that the intoxication caused the injury. Therefore, a positive drug test alone might not provide a defense to a worker's compensation claim.