This is done to verify whether the accident was an ordinary event or resulted from drug influence. The employer might have no problem with recreational use, but in such cases, other parties such as insurers are also involved. Failing a test under such circumstances is likely to have negative ramifications. Some employers also do random drug tests. Such tests are usually unannounced and might only be done on a small percentage of employees. Mostly, such tests are carried out for research purposes so you might get away with failing one. Just as the reasons for drug testing vary, there are many reasons too why one could be searching for ideas on how to pass a drug test. The most important thing is to be fully informed.