Almost a year ago, I twisted my knee when my foot slipped on a stair at work. I have continued to work since then but the knee has gotten MUCH worse. I did not file an accident report with my employer because, at the time, did not seem too bad. What can I do to see about getting treatment for my knee now?
A traumatic event occurring in the course of employment, is generally the definition of an industrial injury in the State of Washington. As long as you can show that the injury occurred while at the work site, it should be allowed and recognized by the Department of Labor and Industries. There is a time limit for filing claims for industrial injuries. A report of accident must be filed with the Department of Labor and Industries within one year of the date of the accident. It is not necessary that you specifically report it to your employer at the time the event occurred.
The one year limit for filing these claims with the Department is strictly upheld by the courts.
I would advise you to go see a doctor immediately, have the doctor help you fill out an accident report form and mail it to the Department of Labor and Industries. The longer you wait, the more you risk not getting it filed within one year of the date of accident. If you go beyond one year without filing the accident report, even if you had ten people willing to sign an affidavit that this knee problem started from an injury occurring in the course of your employment, you would be prohibited, by law, from filing such a claim.

