ALCOAST 287/25 - JUN 2025 CHANGES IN THRESHOLD LIMIT VALUE-TIME WEIGHTED AVERAGE (TLV-TWA) AND ELIMINATION OF THE THRESHOLD LIMIT VALUE-SHORT TERM EXPOSURE LIMIT FOR BENZENE

R 261820Z JUN 25 MID120002037757U
FM COMDT COGARD WASHINGTON DC
TO ALCOAST
BT
UNCLAS
ALCOAST 287/25
SSIC 6230
SUBJ: CHANGES IN THRESHOLD LIMIT VALUE-TIME WEIGHTED AVERAGE
(TLV-TWA) AND ELIMINATION OF THE THRESHOLD LIMIT VALUE-SHORT TERM
EXPOSURE LIMIT FOR BENZENE
A. Threshold Limit Values (TLVS) and Biological Exposure Indices
(BEIS), ACGIH, NOTAL
B. Occupational Medicine Manual, COMDTINST 6260.32
C. Safety and Environmental Health Manual, COMDTINST 5100.47D
D. Aeronautical Engineering Maintenance Management Process Guide,
CGTO PG-85-00-110-A
E. Marine Safety Manual, Volume I, Administration and Management,
COMDTINST 16000.6
F. MEMO DTD 07 APR 2025- "Documentation of Test Result for Airborne
Concentration of Benzene on the Marine Chemist's Certificate for
Spaces to be Entered BY USCG Personnel"
1. This ALCOAST reflects changes to benzene threshold limit values
(TLV) and short-term exposure limits (STEL) exposure standards
applicable to all personnel, in accordance with REF (A).
2. Benzene is a carcinogenic chemical found in many fuels.
Modifications to existing safe work practices are required to
protect personnel who encounter benzene in the work environment
such as marine safety personnel and aircraft fuel handlers. Until
such time that REFs (B)-(E) are updated, the interim confined space
entry guidance provided in this message shall be followed.
3. Symptoms associated with acute overexposure to benzene include:
drowsiness, dizziness, fast or irregular heartbeat, headaches,
tremors, confusion and unconsciousness. If personnel experience any
of these symptoms following exposure to benzene, they should seek
medical care from their primary care physician for an acute exposure
examination following the following the medical examination protocol
for benzene found in REF (B). Additionally, if care above first aid
is necessary than the unit must submit a mishap report following the
guidance contained in REF (C) using the eMisReps system located at:
(Copy and Paste URL Below into Browser)

https://hswl.uscg.mil

4. Per REF (A), the TLV-time weighted average (TLV-TWA) for benzene
has been lowered from 0.5 parts per million (ppm) to 0.02 ppm and
the TLV-short term exposure limit (TLV-STEL) has been eliminated.
5. TLV-TWA is defined as the TWA concentration for a conventional
8-hour workday and a 40-hour workweek, to which it is believed that
nearly all workers may be repeatedly exposed, day after day, for a
working lifetime without adverse effect.
6. REF (A) eliminated the TLV-STEL, which is defined as a 15-minute
TWA exposure that should not be exceeded at any time during a
workday, even if the 8-hour TWA is within the TLV-TWA.
7. The current Multi-Gas-Meter (MGM) issued to Prevention and
Response personnel, the MSA Altair 4XR, lacks the ability to detect
volatile organic compounds (VOCs), including benzene, at any level.
8. As the MGMs cannot detect benzene, the Marine Chemist Certificate
remains the primary control for marine inspectors to prevent
exposures. Marine Chemists clearing spaces will: verify previous
three cargoes for the presence of benzene, specifically sample for
benzene using instrumentation sufficient to detect benzene
concentrations at the revised threshold and report those values
on the marine chemist certificate posted.
9. Effective immediately, marine safety personnel are not authorized
to enter a confined space that has previously carried benzene or any
space that previously carried or may contain benzene (including tank
vessel pump rooms), or confined spaces immediately adjacent to
spaces that carried or may contain benzene without a marine chemist
certificate that specifically states the detected benzene
concentration is below the 0.02 ppm threshold.
    a. If concentration level is at or above 0.02 ppm, entry is
NOT authorized.
    b. If the concentration level is below 0.02 ppm, entry is
permitted given a properly issued and maintained Marine Chemist
Certificate designates the space as "SAFE FOR WORKERS".
10. As a reminder, Coast Guard personnel may enter confined spaces
initially certified by a Marine Chemist and then maintained by a
Shipyard Competent Person only if:
    a. The shipyard's Health and Safety Program has been evaluated
and found to be satisfactory.
    b. The Shipyard Competent Person's equipment is capable of
testing for the same thresholds and appropriately calibrated. If in
doubt, require a new Marine Chemist Certificate prior to entry.
11. As before, should an MGM alarm, personnel must egress and take
actions in accordance with applicable Coast Guard; unit policies;
and Federal regulations. Contact your servicing Safety and
Environmental Health Officers (SEHOs) with questions regarding
potential acute exposure events.
12. Fuel cell inspections and maintenance pose similar risks to
aircraft maintenance personnel. Aircraft maintenance personnel must
continue to utilize supplied air respirators when conducting fuel
cell maintenance and depuddling operations following REF (D) and
applicable maintenance procedure cards.
13. Dermal absorption poses a significant carcinogenic risk when
working in spaces that previously contained benzene, underscoring
the need for strict protective measures. Personnel are reminded to
wear all required personal protective equipment (PPE) to minimize
skin absorption and prevent cross-contamination.
14. The above changes will be incorporated into the next revisions
of REFs (B)-(E).
15. Points of Contact: Office of Safety & Environmental Health
(CG-1K3) CAPT Patrick Wallace, (571) 608-0716,
Patrick.S.Wallace@uscg.mil; Office of Health Services (CG-1K2),
CDR Dara Lee, (202) 372-0000, Dara.Lee@uscg.mil; Office of
Inspections & Compliance (CG-5PC) CDR Kim Chesteen, (202) 372-1430,
Kimberly.B.Chesteen@uscg.mil; Local unit support: Health, Safety
and Work-Life Service Center SEHOS:
(Copy and Paste URL Below into Browser)

https://uscg.sharepoint-mil.us/sites/hswlsc/SafeEvHealth/SitePages/
Contacts.aspx

16. RADM Paul Jung, Assistant Commandant for Health, Safety, and
Work-Life (CG-1K) and RADM Wayne Arguin, Jr. Assistant Commandant
for Prevention Policy (CG-5P), send.
17. Internet release is authorized.