49 CFR Part 40: DOT Drug and Alcohol Testing Procedures

49 CFR Part 40 is the Department of Transportation’s procedure manual for workplace drug and alcohol testing, and it tells every party in the chain — employer, collector, laboratory, Medical Review Officer, breath alcohol technician and Substance Abuse Professional — exactly how a DOT test must be conducted, verified, reported and acted on. It does not tell you who has to be tested or how often; for motor carriers that comes from 49 CFR Part 382, and the two rules have to be read together.

That split is the single most misunderstood thing about DOT testing, and it costs carriers money. You can run exactly the right number of random tests and still fail an audit because the collection site skipped a step, or because you removed a driver on a laboratory report the MRO had not yet verified.

What is 49 CFR Part 40 and who does it cover?

Part 40 opens by saying what it is: it “tells all parties who conduct drug and alcohol tests required by Department of Transportation (DOT) agency regulations how to conduct these tests and what procedures to use” (49 CFR 40.1(a)). It reaches transportation employers, safety-sensitive employees — including self-employed individuals, contractors and volunteers where a DOT agency covers them — and service agents (40.1(b)).

Two employer obligations sit right at the front and are worth memorising:

• You own the outcome. 49 CFR 40.11(a) makes you responsible for meeting all applicable requirements of the part, and 40.11(b) makes you responsible for the actions of your officials, representatives and agents — including service agents. Outsourcing to a consortium/third-party administrator (C/TPA) does not outsource the liability.
• DOT tests stand alone. 49 CFR 40.13(a) requires DOT tests to be “completely separate from non-DOT tests in all respects,” and 40.13(b) requires the DOT test to be conducted and completed first. If you also run a company hair test or a 10-panel, it is a separate collection with a separate specimen.

Only five drugs or classes of drugs are on a DOT panel under 49 CFR 40.82: marijuana metabolites, cocaine metabolites, amphetamines, opioids, and phencyclidine. The same section forbids the laboratory from testing a DOT specimen for anything else.

How does Part 40 relate to Part 382?

Think of them as how and who.

Question	Answered by
Which drivers are covered, and which tests must I run?	Part 382 (382.103, 382.301, 382.305)
At what minimum random rates?	Part 382 (382.305 — 50% for controlled substances, 10% for alcohol, subject to change by the Administrator via Federal Register notice)
How is the specimen collected and verified?	Part 40 (Subparts E, F, G)
What counts as a refusal?	Part 40 (40.191, 40.261)
How does a driver get back to work?	Part 40 Subpart O, with Clearinghouse gating in 382.701(d)

The seam between them shows up in hiring. 49 CFR 40.25(a)(1) requires an employer to obtain written consent and request two years of prior DOT testing history before a new hire performs safety-sensitive work. But 40.25(a)(2) then says an FMCSA-regulated employer satisfies that duty through the FMCSA Drug and Alcohol Clearinghouse under 49 CFR 382.71(a) — while still having to make the traditional 40.25 request for any non-FMCSA DOT history the driver has (for example, a prior PHMSA or FAA covered job).

Two hard deadlines live in that section. Under 40.25(d) you must not let the driver perform safety-sensitive functions after 30 days from first performance unless you have obtained the information or documented a good-faith effort to obtain it. Under 40.25(i) you retain that record for three years from the driver’s first day of safety-sensitive duty. This is exactly the material that also belongs in the driver qualification file.

What actually happens during a DOT specimen collection?

The collection subparts are long and prescriptive, but the parts that generate carrier findings are few.

Insufficient specimen (“shy bladder”). Under 49 CFR 40.193(b)(1)(ii) the collector urges the employee to drink up to 40 ounces of fluid, distributed reasonably over up to three hours, or until a sufficient specimen is produced. If nothing sufficient arrives within three hours of the first unsuccessful attempt, the collection is discontinued and the DER is notified (40.193(b)(1)(iv)). For an oral fluid collection the window is one hour and up to 8 ounces of fluid (40.193(b)(2)). Declining to drink is not a refusal.

The five-day medical evaluation. When a collection ends short, 49 CFR 40.193(c) requires the employer, after consulting the MRO, to direct the employee to obtain an evaluation from a licensed physician within five days. The same five-day clock applies to insufficient breath under 40.265(c). Only if the physician finds no adequate basis for a medical explanation does the MRO record a refusal (40.193(d)(2)).

Direct observation. Under 49 CFR 40.67(b), every return-to-duty and follow-up drug test is collected under direct observation — no exceptions, no discretion. 40.67(a) adds employer-directed observed recollections after an invalid result with no adequate medical explanation, after a split specimen could not be tested, and in the narrow negative-dilute creatinine band of 2 to 5 mg/dL.

What does the Medical Review Officer do, and what may you do before they finish?

The MRO is the licensed physician who stands between a laboratory report and an employment consequence. Nothing is a “positive” until the MRO verifies it.

That is why 49 CFR 40.21(a) prohibits employers from “standing employees down” — temporarily pulling them from safety-sensitive duty on the strength of a confirmed laboratory positive, adulterated or substituted report — unless the employer holds a waiver granted by the concerned DOT agency. Acting early is a violation in its own right.

Once the MRO does report, 49 CFR 40.23 is unambiguous about timing:

• Verified positive: remove the employee from safety-sensitive functions immediately, on the initial report. Do not wait for the written report or the split result (40.23(a)).
• Verified adulterated or substituted: treat as a refusal and remove immediately (40.23(b)).
• Alcohol result of 0.04 or higher: remove immediately. Result of 0.02 to 0.039: temporarily remove as the DOT agency rules provide (40.23(c)).
• No return to safety-sensitive duty until the Subpart O return-to-duty process is complete (40.23(d)).
• Never alter a result transmitted by an MRO, BAT or C/TPA (40.23(i)).

The driver’s remedy is the split specimen. Under 49 CFR 40.171(a) they have 72 hours from MRO notification to request a test of the split, verbally or in writing, and 40.173(b) puts the cost on the employer — you may not make the test contingent on the driver paying.

For context on where the numbers come from, these are the urine cutoff concentrations set out in 49 CFR 40.85:

Initial test analyte	Initial cutoff	Confirmatory cutoff
Marijuana metabolite (THCA)	50 ng/mL	15 ng/mL
Cocaine metabolite (benzoylecgonine)	150 ng/mL	100 ng/mL
Codeine / morphine	2,000 ng/mL	2,000 ng/mL
Hydrocodone / hydromorphone	300 ng/mL	100 ng/mL
Oxycodone / oxymorphone	100 ng/mL	100 ng/mL
6-Acetylmorphine	10 ng/mL	10 ng/mL
Phencyclidine	25 ng/mL	25 ng/mL
Amphetamine / methamphetamine	500 ng/mL	250 ng/mL
MDMA / MDA	500 ng/mL	250 ng/mL

What counts as a refusal to test?

A refusal carries the same consequence as a positive, and 49 CFR 40.191(c) and 40.261(b) both state that the consequences “cannot be overturned or set aside by an arbitration, grievance, State court or other non-Federal forum.”

One structural point decides most disputes: the collector, BAT or MRO documents the conduct, but the employer decides whether it was a refusal. Both 40.191(d)(1) and 40.261(c)(2) call this the employer’s “non-delegable duty” under 49 CFR 40.355(i). Your C/TPA cannot make that call for you.

Behaviour	Refusal on a drug test (40.191)	Refusal on an alcohol test (40.261)
Failing to appear for a test within a reasonable time (except pre-employment)	Yes — 40.191(a)(1)	Yes — 40.261(a)(1)
Leaving the testing site before the process is complete	Yes — 40.191(a)(2)	Yes — 40.261(a)(2)
Failing to provide a specimen / adequate breath or saliva	Yes — 40.191(a)(3)	Yes — 40.261(a)(3)
Insufficient specimen with no adequate medical explanation	Yes — 40.191(a)(5)	Yes — 40.261(a)(4)
Refusing a directed medical examination or evaluation	Yes — 40.191(a)(7)	Yes — 40.261(a)(5)
Refusing to permit a directly observed or monitored collection	Yes — 40.191(a)(4), (a)(9)	Not applicable
Possessing or wearing a device to interfere with collection	Yes — 40.191(a)(10)	Not applicable
Admitting adulteration or substitution to the collector or MRO	Yes — 40.191(a)(11)	Not applicable
Verified adulterated or substituted result	Yes — 40.191(b)	Not applicable
Refusing to sign the certification at Step 2 of the ATF	Not applicable	Yes — 40.261(a)(6)
Failing to cooperate with any part of the testing process	Yes — 40.191(a)(8)	Yes — 40.261(a)(7)

Two carve-outs matter. An employee who leaves a pre-employment collection site before the testing process commences has not refused (40.191(a)(2)–(3)). And refusing a non-DOT test or form is not a DOT refusal and carries no DOT consequence (40.191(e), 40.261(d)).

How does a driver get back to work after a violation?

Subpart O is the return-to-duty process, and 49 CFR 40.285(a) is categorical: an employee who has violated a DOT drug and alcohol regulation “cannot again perform any DOT safety-sensitive duties for any employer” until the SAP evaluation, referral and education/treatment process is complete. Under 40.285(b) a violation means a verified positive, an alcohol result of 0.04 or greater, a refusal, or any other violation of a DOT agency’s drug or alcohol prohibition.

The employer’s duties are narrower than most people assume:

1. Give the driver a SAP list, free. 49 CFR 40.287 requires you to provide every violating employee — including an applicant or new hire — a list of SAPs readily available and acceptable to you, with names, addresses and phone numbers, at no charge to the employee.
2. You need not pay for treatment. 49 CFR 40.289(a) says you are not required to provide a SAP evaluation or the recommended education or treatment. But 40.289(b) says that if you offer the driver a route back to safety-sensitive duty, you must first ensure a qualified SAP evaluation and successful compliance with its recommendations. Who pays is left to the parties (40.289(c)).
3. Return-to-duty test. Under 49 CFR 40.305(a) the test cannot occur until the SAP determines successful compliance, and the driver must produce a negative drug result and/or an alcohol result below 0.02 before resuming duties. Under 40.305(b), meeting the conditions does not entitle the driver to their job back — that stays a personnel decision.
4. Follow-up testing. 49 CFR 40.307(d) sets the floor: at least six unannounced follow-up tests in the first 12 months of safety-sensitive duty after return. The SAP may require more and may extend testing across the following 48 months (40.307(d)(2)). Under 40.307(g), neither you nor the SAP may tell the driver the schedule.

Three operational traps sit in 49 CFR 40.309: you schedule the dates but they must be unannounced with no discernible pattern (40.309(b)); you cannot substitute a random test for a follow-up test (40.309(c)); and a cancelled follow-up test does not count and must be recollected (40.309(d)). And under 40.307(e) the plan travels — if a driver with four remaining tests joins your fleet, those four become your obligation, discovered through the 40.25 / Clearinghouse inquiry.

SAP credentials are fixed by 49 CFR 40.281(a): a licensed physician, licensed or certified social worker, psychologist, employee assistance professional, state-licensed marriage and family therapist, or a drug and alcohol counsellor certified by an organisation listed by DOT’s ODAPC. A treatment centre intake counsellor who does not hold one of those is not a SAP.

What auditors actually check

During a compliance review the investigator is not re-testing anybody. They are reading paper, and Part 40 tells them what paper must exist.

• Production speed. 49 CFR 40.333(d) allows a service agent to hold your records, but you must be able to produce them at your principal place of business — and it names the motor carrier case explicitly: “when an FMCSA inspector requests your records, you must ensure that you can provide them within two business days.”
• Retention periods. Five years for alcohol results of 0.02 or greater, verified positives, documented refusals, SAP reports, and all follow-up tests and schedules (40.333(a)(1)). Three years for previous-employer information obtained under 40.25 (40.333(a)(2)). Two years for EBT calibration and maintenance records (40.333(a)(3)). One year for negative and cancelled results (40.333(a)(4)).
• Storage. Records must be kept in a location with controlled access (40.333(c)), and electronic records must be legible, organised and reproducible in a “rapid and readily auditable manner” (40.333(e)).
• Pre-employment paper trail. Written consent, the query or request, the response, or the documented good-faith effort — plus proof it was completed inside the 30-day window of 40.25(d).
• Removal timing. Whether the driver actually came off safety-sensitive duty on the date the MRO reported, per 40.23(a).
• Return-to-duty file. SAP initial report, follow-up evaluation report, the written follow-up testing plan, and the negative RTD result — the set required by 40.305 and 40.307.

Carriers who keep testing records where the qualification file lives tend to fare better here, which is why Fleetive’s compliance module stores testing documents against the driver record with their own retention clocks rather than in a separate binder. If you want to pressure-test your own file room first, the DOT audit readiness quiz walks the same ground.

Most common violations

1. Acting on a laboratory result before MRO verification — a straight 40.21(a) stand-down violation, and one that also exposes the carrier to a wrongful-termination claim.
2. Leaving a driver on the road after a verified positive because the written report or split result had not arrived. 40.23(a) says immediately.
3. Letting the C/TPA declare a refusal. The employer has the non-delegable duty under 40.355(i), and an undocumented employer decision looks like no decision at all.
4. Missing previous-employer records past 30 days with no documented good-faith effort — 40.25(d).
5. Blending DOT and non-DOT collections, most often by testing a DOT specimen on a wider panel, contrary to 40.13(a) and 40.82.
6. Treating a dilute negative as a violation. 40.197 governs dilutes; only the specified narrow band triggers an observed recollection.
7. Counting a random test as a follow-up test — prohibited by 40.309(c) — or never picking up an inherited follow-up plan under 40.307(e).
8. Retention gaps, usually negative results discarded early or SAP reports filed with the driver’s HR file and lost at termination.

Where to read the rule

The full text is worth having open when a real case arrives. Cornell’s Legal Information Institute mirrors the CFR at 49 CFR Part 40, and the refusal section most often argued about is 49 CFR 40.191. DOT’s Office of Drug and Alcohol Policy and Compliance also publishes plain-language guidance that interprets the same text.

If you are building a program from scratch, work outward from the mode rule rather than from Part 40: start with Part 382 for who and when, then use Part 40 for how. Drivers looking for their own side of this — what a positive means for a CDL, and what the Clearinghouse shows — should start in the driver resources library. Carriers building the wider program can work through the DOT compliance guide and the FMCSA regulations overview, or browse the rest of the 49 CFR reference library.

This page is a plain-English summary of a federal regulation, not legal advice. Regulations are amended; confirm the current text on eCFR or Cornell LII before you rely on it, and consult qualified counsel or your DOT consultant for your specific situation.