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Oregon OSHA revises tethered logging research variance provisions

July 20, 2022 - The Department of Consumer and Business Services, pursuant to OAR 437-001-0430, hereby gives notice that Oregon OSHA has revised its general provisions for all currently active tethered logging research variances in an effort to better ensure worker safety and to assist employers. While the revised provisions contain minimal changes, significant changes were made to provisions 4, 7, 8, and 11, as described below.

Key changes to provision 4:

The revised research variance provisions clarify previous and current cab protection requirements for base machines if employers allow employees to occupy the base machine cab during tethered logging operations. If employers allow employees to occupy base machine cabs while a tether line is under tension from steep slope machine (SSM) movement, the base machines must be equipped with a cab that provides tip-over protection in accordance with OAR 437-007-0775(14)(a),(b), and (c).

Key changes to provision 7:

The revised research variance provisions changes the following tether line inspection and replacement requirements:

  • Inspections of the entire length of tether lines are no longer required prior to the start up of each tethered logging project. Instead, only the portion of line used during the previous project plus an additional 100 feet must be inspected prior to the start up of each tethered logging project.
  • Replacement of tether lines are no longer required after 2000 hours of use, unless the line is damaged beyond repair, or the tether logging system manufacturer requires replacement after a specified number of hours of use. Instead, inspection of the entire length of each tether line and drum connection must be conducted by a competent person at least every 2,000 hours of use.

Key changes to provision 8:

The revised research variance provisions specify that if communication between the SSM and base machine becomes weak or is lost, discontinue work and move back to where there is an adequate communication signal. Also, the changes emphasize that base machines must be set up to minimize unintended movement, and that a device that senses excessive base machine movement must be effectively used and maintained to immediately notify the SSM operator during operation. Base machine anchorage and movement-sensing devices must be inspected daily prior to use and after excessive base machine movement.

Key changes to provision 11:

The revised research variance provisions specifies that base machines must not be repositioned or moved while tether lines are under tension from the SSM.


Anyone wishing to express views or arguments, orally or in writing, must submit a written request for a public hearing within 20 days of the date of this notice, along with written comments to the address provided. A public hearing will be held if the division receives requests from ten or more people or from an association with ten or more members. If sufficient requests are received to hold a public hearing, interested persons will be notified of the date and time of the hearing.

Department of Consumer and Business Services
Oregon OSHA
Standards & Technical Resources
P.O. BOX 14480
Salem, OR  97309-0405

IF AN INTERESTED PERSON WISHES TO EXPRESS ANY DATA, VIEWS OR LEARN OF THE DECISION, CONTACT THE OFFICE LISTED ABOVE.


2022 Revised Tethered Logging Research Variance Provisions

  1. When a variance term or requirement, herewith in, conflicts with a recommendation or specification by the tethered logging system manufacturer or machine manufacturer, the term, requirement, recommendation, or specification that would provide the higher level of safety for employees must be followed.
  2. Forest activities not covered under the rule for which the variance is issued must comply with all applicable Division 1, 2, and 7 rule requirements including, but not limited to, reporting fatalities and hospitalizations to Oregon OSHA, emergency medical plans, requirements for cutting trees and mechanical falling, securing machines, working alone, employee involvement, and supervisory responsibilities.
  3. Tethered logging operations must not create a hazardous condition for workers, including any subsequent hand felling operations. Operations must communicate harvest plans with hand fallers when applicable, and have hand fallers work first if possible. Operations must ensure all piles are stable on the hillside if fallers will be working below felled timber.
  4. Tethered logging steep slope machines (SSMs) must meet all applicable protective structure requirements under OAR 437-007-0775, be equipped with a certified roll-over protective structure (ROPS), and have at least a 4-point operator restraint system approved by the machine's manufacturer. Base machines used for tethered logging must be equipped with a cab that provides tip-over protection in accordance with OAR 437-007-0775(14)(a),(b), and (c), if an employee is allowed to be in the cab while the tether line(s) is under tension from SSM movement.
  5. The tethered logging winch system must be designed and constructed for tethered logging applications by the original equipment manufacturer (OEM), or approved for tethered logging applications in writing by the OEM or a registered professional engineer.
  6. The tethered logging system must be operated, inspected, and maintained in accordance with the manufacturer's recommendations, specifications, and limitations; or if no manufacturer's recommendations exist, then by the recommendations of a registered professional engineer. Operators must ensure all machines, equipment, and attachments are secured to prevent movement and unintended operation during inspections and maintenance activities. Tethered logging systems and components not in safe operating condition must be removed from service until repaired or replaced by a qualified person.
  7. Tether lines must be one continuous piece of wire rope (not spliced) and have a rated breaking load according to the tethered logging system manufacturer's recommendations and specifications. Tether lines must be repaired (shortened only) or replaced if there is evidence of chafing, sawing, crushing, kinking, crystallization, bird-caging, significant corrosion, heat damage, or other damage that has weakened the tether line. At a minimum, tether line inspections must be conducted by a competent person as follows:
    • Daily line inspections: Inspect the first 50 feet of each tether line prior to use. Such inspections may be conducted at the end of the day in preparation for the next day of use by the same operator.
    • Unit startup line inspections: Inspect the maximum portion of tether line(s) used during the previous project plus an additional 100 feet. Such inspections may be conducted at the end of a project in preparation for the next project startup.
    • 2,000-hour line inspections: Inspect the entire length of each tether line and drum connection after 2,000 hours of use. Such inspections may be conducted anytime during the year and can substitute a project startup inspection if done between projects. Lines may be upended during annual inspections following any tethering system manufacturer's recommendations and specifications.
  8. The tether line winch system must be synchronized with the SSM travel to ensure continuous tether line tension during operation. The winch must be designed and used in a manner to prevent line tension from exceeding 33 percent of the rope's rated breaking load under operating conditions. The operator must effectively use an immediate and self-reliant, or automated, way to identify tether line tension, winch rotation and speed, and the amount of line on and off the drum. If communication between the SSM and base machine becomes weak or is lost, work must be discontinued, and moved back to where there is an adequate communication signal. Base machines must be set up to minimize unintended movement. A device that senses excessive base machine movement must be effectively used and maintained to immediately notify the SSM operator during operation. Base machine anchorage and movement sensing devices must be inspected daily prior to use and after excessive base machine movement.
  9. All tether line assembly components must be rated with a greater safe working load than each tether line (wire rope). Tether line attachment points and hitches must be engineered and certified to maintain a safety factor equal to or greater than the recommendations and specifications of the tether logging system manufacturer. Quick nub ferrules (split-wedge ferrules) must not be used for normal operations (Note: Quick nubs may only be used during an emergency). Inspections of tether line assembly components and equipment (except drum connection as specified under #7) including hitches, shackles and pins, sockets, sheaves, winches, machines, anchors, etc., must be performed daily by a competent person prior to use.
  10. Operators must have sufficient training and experience operating tethered machines on slopes under 50 percent for each type of tethered logging system they are authorized to use prior to operating tethered machines on slopes over 50 percent.
  11. Base machines should be repositioned when possible to maintain straight tether lines. Base machines must not be repositioned or moved while tether lines are under tension from the SSM. Operators must have sufficient training and experience to safely redirect tether lines (side wash). When using a stump or tree to side wash tether lines, the line deflection angle should be less than 40 degrees unless the operator has determined that a greater angle can safely be used. Operators should consider using a block for tether line deflection angles greater than 40 degrees.
  12. The employer must establish and use procedures for operators to report unsafe conditions to a supervisor or competent person. Such conditions must be corrected prior to resuming tethered logging operations. Procedures must also include steps to take in the event of equipment breakdown and upset conditions.
  13. All remotely operated equipment must have signage that effectively warns employees and others that machines and lines may start, stop, or move without warning. All employees working in close proximity to tethered logging operations must receive training that enables them to recognize the potential hazards involved and to maintain safe distances.
  14. All tethered logging operations must be planned by the operator and a competent person. Plans must be updated when weather and ground conditions change. Items to consider during site-specific planning must include, but are not limited to, the following:
    • Experience and skill level of the operator
    • Slope limitations of the equipment if specified by the manufacturer
    • Areas to be hand felled, if applicable
    • Soil and terrain conditions
    • Environmental conditions
    • Weather conditions
    • Impaired vision conditions
    • Communication with affected personnel
    • Direction of travel
    • Requirements for turning the machine on slopes
    • Load sizes and haul routes
    • Location of anchor machine and method to be used for effective anchorage
    • Potential fire hazards
    • Any other condition that can adversely affect operations
  15. Tethered logging operations must provide Oregon OSHA's Technical Section staff, or their Oregon OSHA Consultation Service designee, the opportunity to conduct annual visits of operations covered under this research variance in a timely manner when requested. Such visits must allow interviews of machine operators.
  16. Tethered logging operators must provide a research variance report in writing to Oregon OSHA on a semi-annual basis during the months of January and July each year the variance is in effect. The report must include the following information:
    • Safety, health, and ergonomic issues identified, including machine tip-over, roll-over and equipment failure events, regardless of incurred bodily injury.
    • Recordable injuries incurred during tethered logging operations and any comparative data for hand felling and cable logging injuries that were incurred at the same worksite. (Note: This provision does not satisfy the reporting requirements under 437-001-0704, Reporting Fatalities and Injuries to Oregon OSHA, nor does it exempt the employer from the requirements under the rule.)
    • Any interventions taken which were not included in, or in conflict with, the provisions in the variance but were necessary to ensure the safety and health of employees.
    • A summary of tether line inspections, and any system repairs or replacements made.
    • Total hours of SSM operation on slopes greater than 50 percent.

    Information listed in #16 must be submitted on the following semi-annual schedule each year the variance is in effect:

    Six-month Reporting PeriodsReport Due Dates
    January through JuneJuly 31
    July through DecemberJanuary 31

    Send research variance reports to:

    Oregon Occupational Safety and Health Division
    David J. McLaughlin
    Standards & Technical Resources, Manager
    350 Winter Street NE
    P.O. Box 14480
    Salem, OR  97309-0405

    List of employers who have been granted a research variance for OAR 437-007-0935(1)(c) and is affected by this variance modification:

    Siegmund Excavation & Construction, Inc. 

    C & C Logging LLC 

    LBA Contract Cutting, Inc. 

    Wolfco Timber Services LLC 

    Ward Contracting, Inc. 

    Campbell Contract Cutting LLC 

    Greenup Enterprises, Inc. 

    Pellham Cutting, Inc. 

    Krume Logging Co. LLC 

    J & L Cutting, Inc. 

    Lone Rock Logging Co. 

    Hart Custom Cutting LLC 

    B & G Logging and Construction LLC 

    Peterson Logging, Inc. 

    Tioga Logging LLC 

    Rice Logging, Inc. 

    Bighorn Logging Corporation 

    Wayne Stone Logging, Inc. 

    R. D. Reeves Construction, Inc. 

    Krume Logging Co. LLC 

    Bruer's Contract Cutting 

    Estremado & Sons, Inc. 

    Cascade West, Inc. 

    Emerald Valley Thinning, Inc. 

    ZB Contract Cutting LLC 

    Dancer Logging, Inc. 

    Mineral Creek Logging & Hauling LLC 

    Weyerhaeuser Company 

    Weyerhaeuser NR Company 

    Plikat Logging, Inc. 

    JBM, Inc. 

    Dean Logging, Inc. 

    S. A. Schuyler & Sons, Inc. 

    Ron Staley Enterprise, Inc. 

    Black Rock Timber 

    Precision Timber LLC 

    List of employers who have been granted a research variance for OAR 437-007-0935(1)(a) and is affected by this variance modification:

    Krume Logging Co. LLC