49 CFR Part 40.25 Drug & Alcohol Background Check Requirements:

40.25 Must an employer check on the drug and alcohol testing record of employees it is
intending to use to perform safety-sensitive duties?
(a) Yes, as an employer, you must, after obtaining an employee's written consent, request the information
about the employee listed in paragraph (b) of this section. This requirement applies only to employees seeking to
begin performing safety-sensitive duties for you for the first time (i.e., a new hire, an employee transfers into a
safety-sensitive position). If the employee refuses to provide this written consent, you must not permit the employee
to perform safety-sensitive functions.
(b) You must request the information listed in this paragraph (b) from DOT-regulated employers who have
employed the employee during any period during the two years before the date of the employee's application or
transfer:
(1) Alcohol tests with a result of 0.04 or higher alcohol concentration;
(2) Verified positive drug tests;
(3) Refusals to be tested (including verified adulterated or substituted drug test results);
(4) Other violations of DOT agency drug and alcohol testing regulations; and
(5) With respect to any employee who violated a DOT drug and alcohol regulation, documentation of the
employee's successful completion of DOT return-to-duty requirements (including follow-up tests). If the previous
employer does not have information about the return-do-duty process (e.g., an employer who did not hire an
employee who tested positive on a pre-employment test), you must seek to obtain this information from the
employee.
(c) The information obtained from a previous employer includes any drug or alcohol test information
obtained from previous employers under this section or other applicable DOT agency regulations.
(d) If feasible, you must obtain and review this information before the employee first performs safetysensitive
functions. If this is not feasible, you must obtain and review the information as soon as possible. However,
you must not permit the employee to perform safety-sensitive functions after 30 days from the date on which the
employee first performed safety-sensitive functions, unless you have obtained or made and documented a good faith
effort to obtain this information.
(e) If you obtain information that the employee has violated a DOT agency drug and alcohol regulation,
you must not use the employee to perform safety-sensitive functions unless you also obtain information that the
employee has subsequently complied with the return-to-duty requirements of Subpart O of this part and DOT
agency drug and alcohol regulations.
(f) You must provide to each of the employers from whom you request information under paragraph (b) of
this section written consent for the release of the information cited in paragraph (a) of this section.
(g) The release of information under this section must be in any written form (e.g., fax, e-mail, letter) that
ensures confidentiality. As the previous employer, you must maintain a written record of the information released,
including the date, the party to whom it was released, and a summary of the information provided.
(h) If you are an employer from whom information is requested under paragraph (b) of this section, you
must, after reviewing the employee's specific, written consent, immediately release the requested information to the
employer making the inquiry.
(i) As the employer requesting the information required under this section, you must maintain a written,
confidential record of the information you obtain or of the good faith efforts you made to obtain the information.
You must retain this information for three years from the date of the employee's first performance of safety-sensitive
duties for you.
(j) As the employer, you must also ask the employee whether he or she has tested positive, or refused to
test, on any pre-employment drug or alcohol test administered by an employer to which the employee applied for,
but did not obtain, safety-sensitive transportation work covered by DOT agency drug and alcohol testing rules
during the past two years. If the employee admits that he or she had a positive test or a refusal to test, you must not
use the employee to perform safety-sensitive functions for you, until and unless the employee documents successful
completion of the return-to-duty process (see paragraphs (b)(5) and (e) of this section).