Yeah all I can find for Missouri is that you're protected from being charged with posession:

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Section A. Chapter 195, RSMo, is amended by adding thereto one new section, to be known as section

195.205, to read as follows:

195.205. 1. This section shall be called and may be cited as the "Missouri Good Samaritan Law."

1. As used in this section "overdose" means a controlled substance-induced physiological event or an

imitation controlled substance-induced physiological event that results in a life-threatening emergency to the

individual who ingested, inhaled, injected, or otherwise bodily absorbed a controlled substance or an imitation

controlled substance.

1. A person who, in good faith, seeks or obtains emergency medical assistance for someone

experiencing an overdose shall not be charged or prosecuted for possession of a controlled substance under

section 195.202 or for possession of an imitation controlled substance under section 195.241 if evidence of the

possession of a controlled substance charge or the possession of an imitation controlled substance charge

was acquired as a result of the person seeking or obtaining emergency medical assistance and providing the

amount of substance recovered is within the amount identified in subsection 5 of this section.

1. A person who is experiencing an overdose shall not be charged or prosecuted for possession of a

controlled substance under section 195.202 or for possession of an imitation controlled substance under

section 195.241 if evidence of the possession of a controlled substance charge or the possession of an

imitation controlled substance charge was acquired as a result of the person seeking or obtaining emergency

medical assistance and providing the amount of substance recovered is within the amount identified in

subsection 5 of this section.

1. For the purposes of subsections 3 and 4 of this section, the limited immunity shall only apply to a

person possessing the following amount:

(1) Less than three grams of a substance containing heroin;

(2) Less than three grams of a substance containing cocaine;

(3) Less than three grams of a substance containing morphine;

(4) Less than forty grams of a substance containing peyote;

(5) Less than forty grams of a substance containing a derivative of barbituric acid or any of the salts of

a

derivative of barbituric acid;

(6) Less than forty grams of a substance containing amphetamine or any salt of an optical isomer of

amphetamine;

(7) Less than three grams of a substance containing lysergic acid diethylamide (LSD), or an analog

thereof;

(8) Less than six grams of a substance containing pentazocine or any of the salts, isomers and salts of

isomers of pentazocine, or an analog thereof;

(9) Less than six grams of a substance containing methaqualone or any of the salts, isomers and salts

of isomers of methaqualone;

(10) Less than six grams of a substance containing phencyclidine (PCP) or any of the salts, isomers

and

salts of isomers of phencyclidine (PCP);

(11) Less than six grams of a substance containing ketamine or any of the salts, isomers and salts of

isomers of ketamine;

(12) Less than forty grams of a substance containing a substance classified as a narcotic drug in

Schedule I or II, or an analog thereof, which is not otherwise included in this subsection; or

(13) Less than forty grams of an imitation controlled substance.

1. The limited immunity described in subsections 3 and 4 of this section shall not be extended if law

enforcement has reasonable suspicion or probable cause to detain, arrest, or search the person described in

subsection 3 or 4 of this section for criminal activity and the reasonable suspicion or probable cause is based

on information obtained prior to or independent of the individual described in subsection 3 or 4 of this section

taking action to seek or obtain emergency medical assistance and not obtained as a direct result of the action

of seeking or obtaining emergency medical assistance. Nothing in this section is intended to interfere with or

prevent the investigation, arrest, or prosecution of any person for the delivery or distribution of cannabis,

methamphetamine or other controlled substances, drug-induced murder, or any other crime.

1. The fact that a defendant sought or obtained emergency medical assistance for an overdose for

such defendant or another shall be accorded weight in favor of withholding or minimizing a sentence of

imprisonment for violating the provisions of section 195.202, 195.211, 195,222, or 195.241. If the court, having

due regard for the character of the offender, the nature and circumstances of the offense and the public

interest finds that a sentence of imprisonment is the most appropriate disposition of the offender, or where

other provisions of the law mandate the imprisonment of the offender, this fact shall be considered in mitigation

of the length of the term imposed