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Freight Carrier · Williston, ND

CASTLE OILFIELD SERVICES

501 48TH AVE W · Williston, ND 58801

AUTHORIZED FOR:
(701) 572-1832 Tap to call
  • MC #1376430
  • USDOT #2496282 USDOT Active
  • 20
    Power Units
  • 19
    Drivers
  • Carrier
    Entity Type

About this carrier

CASTLE OILFIELD SERVICES is a Williston, ND freight carrier that is authorized for: in the state of North Dakota. This company has 20 truck(s) in their fleet and 19 truck drivers. Their motor carrier number is MC-1376430 and their USDOT number is 2496282.

Sourced from FMCSA SAFER · last filed 01/29/2026 · last updated Jul 22, 2026.

Carrier Details

  • Legal Name COS LLC
  • Operating Status AUTHORIZED FOR:
  • MCS-150 Filed 01/29/2026
  • MCS-150 Mileage 251,164 (2025)

Authority & Operations

Operation Classification
  • Authorized for Hire
Carrier Operation
  • Interstate

Cargo Authorized

  • Liquids/Gases
  • Oilfield Equipment

Operating Territory

Map of states where this carrier has roadside inspections North Dakota — 7 inspections (past 24 months) Wyoming — 3 inspections (past 24 months) South Dakota — 1 inspection (past 24 months) Texas — 1 inspection (past 24 months) Texas — 1 inspection (past 24 months)

Inspection activity   Inspected in 4 states over the past 24 months: ND (7), WY (3), SD (1), TX (1). Home base: Williston, North Dakota.

Safety Record

1 Acute/Critical 9 Severe Violations Updated 7 days ago

Crashes (24 mo)

  • 0
    Fatal
  • 2
    Injury
  • 2
    Tow
  • 4
    Total

Behavior Categories (BASICs)

CategoryMeasureViolations Unsafe Driving 0.86 3 Crash Indicator Not Public — Hours of Service 1.5 3 Vehicle Maintenance 18.54 7 Drugs / Alcohol 0 0 Hazmat Not Public — Driver Fitness 2.64 6

Inspection Summary

  • 12
    Total
  • 2
    Clean
  • 10
    With violations

24-month window ending Jun 26, 2026

Violations Cited 51 unique codes

Critical 24

  • 393.75A3-TAOLTires - All others, leaking or inflation less than 50% of the maximum inflation pressure on tire not equipped with ATIS1× OOS×1 SW 8
  • 383.23(a)(2)Operating a CMV without a CDL1× OOS×1 SW 8
  • 383.23A2-LCDLNLicense (CDL) - Operate a CMV and does not possess a valid CDL1× OOS×1 SW 8
  • 391.11B5-LNCDLNVLLicense - Operate a CMV without a valid operators license, issued by one State or jurisdiction1× OOS×1 SW 8
  • 393.75C-TAOTD-LT2/32Tires - Less than 2/32 inch tread depth1× SW 8
  • 393.207F-SDASSuspension - Deflated air suspension1× OOS×1 SW 7
  • 393.207A-SUBLSuspension - U-bolt, u-bolt bottom plate, or other axle clamp bolt loose/cracked/broken/missing.1× OOS×1 SW 7
  • 393.209D-STGBLSteering - Gear box mounting bolt loose1× OOS×1 SW 6
  • 393.9A-LSLIWRLighting - Stop lamps - Both inoperative when required to be on1× OOS×1 SW 6
  • 393.9A-LTSILighting - Turn signal - Any inoperative on the rearmost vehicle.1× OOS×1 SW 6
  • 395.8A1-HOSPHOS (Property) - Failing to have a record of duty status using the method prescribed3× OOS×3 SW 5
  • 393.43D-BBrake - Missing or inoperable breakaway braking system on a trailer(s) or converter dolly2× OOS×2 SW 4
  • 396.3A1-BALRAir Brake - Fails air loss rate test1× OOS×1 SW 4
  • 393.43(d)No or defective automatic trailer brake1× OOS×1 SW 4
  • 393.43DBMABrake - Breakaway not attached to the towing vehicle1× OOS×1 SW 4
  • 393.75G-TAOWTires - All others, weight carried exceeds tire load limit1× OOS×1 SW 3
  • 396.3A1-FFuel - Dripping leak.1× OOS×1 SW 3
  • 393.75G-TFWETLTires - Front, weight carried exceeds tire load limit1× OOS×1 SW 3
  • 393.70D-CDTSDDCoupling - Trailer, safety devices wire/chain damaged.1× OOS×1 SW 3
  • 393.23PTAll required lamps on towed vehicle inoperative due to no electrical connection1× OOS×1 SW 2
  • 391.11(b)(4)Medical (Certificate) - Operating a CDL (passenger or property carrying) vehicle that is non-excepted and the driver has self-certified as excepted interstate or excepted intrastate with the state driver's licensing agency.1× OOS×1 SW 2
  • 396.3A1-HCMHubs - Bearing cap, plug or filler plug missing or broken1× OOS×1 SW 2
  • 392.9A2-CCargo - Vehicle components or dunnage not secured1× OOS×1 SW 1
  • 396.3(a)1BOSBrake - Defective brake(s) are equal to or greater than 20% of the service brakes on the vehicle/combination3× OOS×3 SW 0

Vehicle Maintenance 23

  • 393.207F-SLASSuspension - Leaking 3 PSI in 5 minutes1× SW 7
  • 393.207A-SAPPCBLMSuspension - Axle positioning part cracked/broken/loose/missing.1× SW 7
  • 393.9A-LRLILighting - Tail lamp - Any inoperative1× SW 6
  • 393.9A-LHLILighting - Headlamp(s) - Any inoperative1× SW 6
  • 393.9A-LBLLighting - Backup lamp inoperative1× SW 6
  • 393.9A-HLLHLighting - Headlamp(s) fail to operate on low and high beam1× SW 6
  • 396.17C-PIOperating a CMV without documentation of a periodic inspection4× SW 4
  • 393.45D-BAir Brake - Audible air leak at a proper connection2× SW 4
  • 393.48A-BIHEHydraulic/Electric Brake - Inoperative other than a steering axle.2× SW 4
  • 393.55D2-BAir Brake - ABS malfunction lamp defective on truck-tractor manufactured on or after March 1, 2001 for towed vehicle.1× SW 4
  • 396.17(c)Operating a CMV without proof of a periodic inspection1× SW 4
  • 393.47(e)Brake Out of Adjustment - Roto, Clamp (Short & Long), DD-3, or Bolt1× SW 4
  • 393.48A-BIBDDrum Brake - Inoperative other than a steering axle1× SW 4
  • 393.53B-BAir Brake - CMV manufactured on or after 10/20/1994 has an automatic airbrake adjustment system that fails to compensate for wear1× SW 4
  • 396.5B-LLubrication - Oil or grease leak1× SW 3
  • 393.95A1Emergency Equipment - Fire Extinguishers - no fire extinguisher present or not properly rated.3× SW 2
  • 393.95(f)Emergency Equipment - Stopped vehicle warning devices missing or improper2× SW 2
  • 393.95(a)No/discharged/unsecured fire extinguisher1× SW 2
  • 393.93A-SBASeatbelts - Drivers seatbelt or passenger seatbelt (if equipped) - missing or defective1× SW 2
  • 393.9A-LILLighting - Identification lamp(s) inoperative1× SW 2
  • 393.201A-FRCLSFrame - Cracked/loose/sagging/broken frame or chassis1× SW 2
  • 393.78Wipers - Inoperative / missing / damaged wipers2× SW 1
  • 393.60(d)Windshield / Windows - Tinting permits less than 70% of light transmittance1× SW 1

Unsafe Driving 2

  • 392.2-SLLTCDState/Local Laws - Failed to obey a traffic control device - Permanent or Temporary - e.g., safety official, signal, sign, light, lane marking, other2× SW 5
  • 392.2-SLLMLState/Local Laws - Failure to maintain lane1× SW 5

Driver Fitness 2

  • 391.41A-MCPCMedical (Certificate) - Operating a commercial motor vehicle without showing proof of a valid medical certification upon request, but presents proof prior to completion of inspection.3× SW 1
  • 383.37(a)Knowingly allowing, requiring, permitting, or authorizing an employee to operate a CMV during any period in which the driver does not have a current CLP or CDL or does not have a CLP or CDL with the proper class or endorsements. An employer may not use a driver to operate a CMV who violates any restriction on the driver's CLP or CDL0× SW 0

Locations

Physical Address
CASTLE OILFIELD SERVICES
501 48TH AVE W
WILLISTON, ND 58801
Mailing Address
COS LLC
PO BOX 1472
WILLISTON, ND 58802

Location on Map

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Related Companies

Other entries in the FMCSA database that share data with this carrier — name, phone, or address overlap. Worth a closer look during vetting.

Same physical address 1

These carriers are registered at the same street + ZIP.

CompanyStatusPower UnitsDriversMC#USDOT#
STATELINE LLC
Legally STATELINE SERVICES INC
Williston, ND
USDOT Active AUTHORIZED FOR:12107440282136935

Same phone number 1

These carriers list the same contact phone number.

CompanyStatusPower UnitsDriversMC#USDOT#
STATELINE LLC
Legally STATELINE SERVICES INC
Williston, ND
USDOT Active AUTHORIZED FOR:12107440282136935

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