Many drug overdose fatalities occur because peers delay or forego calling 911 or Security Services for fear of prosecution. Researchers have identified this as a barrier to the ideal first response of calling emergency services. 

Washington's Good Samaritan Law (RCW 69.50.315) provides some protection for a rescuer/bystander when calling 911 or Security Services to save a life, even if drugs or alcohol are at the scene, and/or the rescuer/bystander has been using drugs and alcohol. 

This information is provided by the Washington Department of Health and Stop Overdose.

No. The law does not protect you from outstanding warrants, probation or parole violations, drug manufacture or delivery, controlled substances homicide, or crimes other than drug possession.

If I don't call 911 but I take the overdose victim to the emergency room, will the law still apply?

The immunity applies to any good faith effort to seek medical help such as calling 911, taking the overdose victim to an emergency room, or running to get a neighbor who is a nurse.

As long as you seek medical help in good faith, you'll receive immunity from drug possession charges. However, if you're the person who gave the victim the drugs that caused the overdose, you may be charged with controlled substances homicide. If you are found guilty, however, the judge may consider your efforts to help when deciding the length of your sentence.

Under this law, could someone under age 21 be cited for alcohol possession if they call 911 due to a likely alcohol overdose at a party?

The 911 Good Samaritan Overdose law was amended in 2013 to also apply to alcohol poisoning. Even if you're under the age of 21, you cannot be charged with possession of alcohol as a minor if you call 911 to help someone suffering from alcohol poisoning. The victim of alcohol poisoning is also protected.

Yes. RCW 69.41.095 says any person or “entity” (e.g., police department, homeless shelter) can obtain, possess, and administer naloxone. It also permits naloxone distribution under a prescriber's standing order.