46 CFR 16.203: Employer, MRO, and SAP drug testing responsibilities

Last reviewed: October 14, 2026

This section sets out who is responsible for meeting the drug testing requirements of this part. Employers must ensure that they and their crewmembers meet the requirements. MROs and SAPs must meet the training requirements and follow the procedures in 49 CFR part 40.

Applies toEmployers, individuals performing Medical Review Officer (MRO) functions, and individuals performing Substance Abuse Professional (SAP) functions.

What it says

  1. Employers must ensure that they and their crewmembers meet the requirements of this part.

    46 CFR 16.203(a)(1)“Employers must ensure that they and their crewmembers meet the requirements of this part.”

  2. Employers are responsible for all the actions of their officials, representatives, and agents in carrying out the requirements of this part.

    46 CFR 16.203(a)(2)“Employers are responsible for all the actions of their officials, representatives, and agents in carrying out the requirements of this part.”

  3. All agreements and arrangements between employers and service agents about implementing DOT drug testing requirements, written or unwritten, are deemed as a matter of law to require compliance with all applicable provisions of this part and DOT agency drug testing regulations.

    46 CFR 16.203(a)(3)“are deemed, as a matter of law, to require compliance with all applicable provisions of this part and DOT agency drug testing regulations.”

  4. Individuals performing MRO functions must meet the training requirements and follow the procedures in 49 CFR part 40.

    46 CFR 16.203(b)(1)“Individuals performing MRO functions must meet the training requirements and follow the procedures in 49 CFR part 40.”

  5. MROs may report chemical drug test results to the Coast Guard for unemployed, self-employed, or individual mariners.

    46 CFR 16.203(b)(2)“MROs may report chemical drug test results to the Coast Guard for unemployed, self-employed, or individual mariners.”

  6. Individuals performing SAP functions must meet the training requirements and follow the procedures in 49 CFR part 40.

    46 CFR 16.203(c)“Individuals performing SAP functions must meet the training requirements and follow the procedures in 49 CFR part 40.”

Common questions

Are employers responsible for the actions of their agents in drug testing?

Yes. Employers are responsible for all the actions of their officials, representatives, and agents in carrying out the requirements of this part.

“Employers are responsible for all the actions of their officials, representatives, and agents in carrying out the requirements of this part.”

What rules must MROs follow?

Individuals performing MRO functions must meet the training requirements and follow the procedures in 49 CFR part 40.

“Individuals performing MRO functions must meet the training requirements and follow the procedures in 49 CFR part 40.”

Can an MRO report drug test results to the Coast Guard for an individual mariner?

Yes. MROs may report chemical drug test results to the Coast Guard for unemployed, self-employed, or individual mariners.

“MROs may report chemical drug test results to the Coast Guard for unemployed, self-employed, or individual mariners.”

What training and procedures apply to substance abuse professionals?

Individuals performing SAP functions must meet the training requirements and follow the procedures in 49 CFR part 40.

“Individuals performing SAP functions must meet the training requirements and follow the procedures in 49 CFR part 40.”

The text of 46 CFR 16.203

Electronic Code of Federal Regulations (eCFR), current as of April 16, 2026 · Read it on eCFR

Employer, MRO, and SAP responsibilities

(a) Employers. (1) Employers must ensure that they and their crewmembers meet the requirements of this part.

(2) Employers are responsible for all the actions of their officials, representatives, and agents in carrying out the requirements of this part.

(3) All agreements and arrangements, written or unwritten, between and among employers and service agents concerning the implementation of DOT drug testing requirements are deemed, as a matter of law, to require compliance with all applicable provisions of this part and DOT agency drug testing regulations. Compliance with these provisions is a material term of all such agreements and arrangements.

(b) Medical Review Officer (MRO). (1) Individuals performing MRO functions must meet the training requirements and follow the procedures in 49 CFR part 40.

(2) MROs may report chemical drug test results to the Coast Guard for unemployed, self-employed, or individual mariners.

(c) Substance Abuse Professional (SAP). Individuals performing SAP functions must meet the training requirements and follow the procedures in 49 CFR part 40.

Sections it refers to

  • 49 CFR part 40

The plain-English explanation on this page was written with AI from the regulation text above and checked automatically before publishing: every quote appears in the text, every number comes from it, and a second model confirmed each statement adds nothing the text doesn't say. Regulation text current as of April 16, 2026. The regulation text governs. RegKnot is not affiliated with the U.S. Coast Guard.