OSHA requirements are set by statute, standards and regulations. Our interpretation letters explain these requirements and how they apply to particular circumstances, but they cannot create additional employer obligations. This letter constitutes OSHA's interpretation of the requirements discussed. Note that our enforcement guidance may be affected by changes to OSHA rules. Also, from time to time we update our guidance in response to new information. To keep apprised of such developments, you can consult OSHA's website at https://www.osha.gov.

November 10, 1999

Mr. Dave Folk
Empire Safety Consulting
4291 Byrum Road
Onondaga, MI 49264

Dear Mr. Folk:

Thank you for your two August 24, 1999 letters to the Occupational Safety and Health Administration (OSHA) requesting interpretation of the lockout/tagout (LOTO) standard and biohazards for postal workers handling mail. Your questions and our replies follow:

Question #1: To what extent must an employer go to secure a hydraulic pump and 220/440 volt electric motor during a lockout? Some pressure usually remains within hydraulic lines on the hydraulic systems, even when the system is shutdown.

Reply: The LOTO standard provides the flexibility for each employer to develop an energy control program, as set forth in 29 CFR §1910.147(c)(1), which is suited to the needs of the particular workplace and the particular types of machines and equipment being maintained or serviced. The extent to which an employer must control hazardous energy depends upon the type of servicing or maintenance work being performed, as well as the type and magnitude of the energy. For example, a hydraulic pump overhaul or the removal of a hydraulic line is much different, and requires different energy control procedures, than working on a piece of equipment that is powered by the hydraulic system. Also, working on the 220/440 volt, nominal, electrical motor is different than working on either the hydraulic system or the equipment powered by the hydraulics.

In some operations, the movement of a simple throw disconnect switch to the "off" mode is a step sufficient to isolate the machine or equipment from the energy source as required by §1910.147(d)(3). In other cases, a series of predetermined steps may be necessary to achieve an orderly shutdown of a machine or piece of equipment in order to safely perform the servicing or maintenance work. This would be the case for the hydraulic pump overhaul or hydraulic line maintenance tasks.

The employer should perform hazardous energy analyses of the workplace equipment and/or machinery to determine the specific procedures for the control of potentially hazardous energy when employees are performing servicing and maintenance activities covered by the standard. This is a prerequisite shutdown preparation step, described in §1910.147(d)(1), which requires authorized employees to have knowledge concerning the type and magnitude of the energy, the hazards associated with the energy to be controlled, and the methods or means to control the energy prior to shutting off the machine or equipment for servicing and/or maintenance activities.

Question #2: If an employer secures the system motor (by service panel lockout) against unauthorized or accidental use and no energy hazards related specifically to the hydraulic system are known to exist, does OSHA commonly accept this adequate lockout protection?

Reply: Yes, but only if all of the provisions of the Lockout/Tagout standard, §1910.147 are met and all hazardous energy sources are effectively controlled. Whether a hydraulic pump and motor is effectively locked or tagged out will have to be determined on a case-by-case basis by the employer, who is ultimately responsible for the safety of employees.

It cannot be overemphasized that employees performing tasks may be exposed to serious hazards if the status of the lockout control can be changed without their knowledge. For this reason, OSHA requires that the authorized employee must be the only person who applies and removes the lockout device(s), unless the §1910.147(e)(3) exception applies.

Question #3: Is it OSHA's policy to require employers to "bleed off" any pressure which may exist within hydraulic systems before accepting the system as effectively "locked out" against unauthorized movement?

Reply: Yes. Hydraulic systems may contain potentially hazardous energy that requires the employer to "bleed off" the pressure. Paragraph 1910.147(d)(5)(i) requires all potentially hazardous stored or residual energy to be relieved, disconnected, restrained, or otherwise rendered safe. Potentially hazardous energy sources are defined as those that can cause injury to employees working in, on, or around machinery or equipment.

With regard to your service panel lockout example, the type of maintenance (i.e., welding adjacent to a pressurized hydraulic machine component) or servicing (i.e., using a sharp tool to clear a material jam adjacent to a pressurized rubber hydraulic hose) work performed will dictate the necessary precautions. If the task(s) can impact the hydraulic system causing a hydraulic liquid hazard, then that energy source must be controlled.

Additionally, simply shutting off a machine, piece of equipment, or process may not completely control the hazardous energy; residual energy may still be present or the potential may exist for unexpected startup or energization of the machine or equipment. Also, if there is a possibility of re-accumulation of stored energy, verification of isolation must be continued until the servicing and maintenance is completed, or until the possibility of such accumulation no longer exists [§1910.147(d)(5)(ii)].

Question #4: You stated that "postal workers are periodically faced with leaking packages of unknown contents and many times it can be determined that the contents are biohazards being sent for lab work." What is OSHA's position as to what type of training the Postal Service must perform to be in compliance with federal standards? Does the situation fall under the "Specialized Training" elements of the Hazard Communication Program or would employees required to perform the clean-up task obtain Hazardous Waste Training? What if the contents of the liquid cannot be identified? Does the training requirement change? (Note: Usually the volume of liquid is small.)

Reply: We're pleased to provide this information for you, and the United States Postal Service (the "Postal Service") publishes documents that also address this subject. For your convenience, we have identified those documents below.

OSHA's Hazardous Waste Operations and Emergency Response standard (HAZWOPER), codified at 29 CFR §1910.120, contains training and other worker protection requirements that may apply to the activities you describe. Biological agents are included in OSHA's definition of a hazardous substance in paragraph (a)(3). Paragraph (q) addresses an employer's obligations when employees are required to respond to an emergency release of a hazardous substance, whether the character of the substance is known or unknown. Postal workers need to be trained according to paragraph (q) of HAZWOPER if they are expected to respond to hazardous substance emergency releases.

You should note that OSHA distinguishes between incidental releases and emergency response efforts. HAZWOPER does not cover the release of a hazardous substance that is limited in exposure potential or toxicity and presents minor safety or health hazards to employees in the immediate work area or those assigned to clean it up. This type of release is referred to as an "incidental release."

A thorough discussion of the distinction between an incidental release and a release that requires an emergency response is provided in Appendix E of OSHA Directive CPL 2-2.59A, (
Inspection Procedures for the Hazardous Waste Operations and Emergency Response Standard, Paragraph (q): Emergency Response to Hazardous Substance Releases). As you may know, the Postal Service accepts limited quantities of hazardous materials for mailing. If a shipper complies with the packaging requirements in the USPS Domestic Mail Manual, the hazards to workers should also be limited. You'll find the hazardous materials "mailability rulings" in Section C023 of the Postal Service Domestic Mail Manual, available at http://pe.usps.gov.

Employees who respond to incidental releases of biological hazards must be protected according to other OSHA standards. For example, if you anticipate that employees will be exposed to blood or other potentially infectious materials (OPIM) in the workplace, then those employees are covered by OSHA's bloodborne pathogens standard, §1910.1030. The bloodborne pathogens standard requires, among other employee protections, employee information and training described in paragraph (g)(2). Likewise, employees exposed to other biohazards from incidental spills must be protected by personal protective equipment in accordance with 1910 Subpart I, Personal Protective Equipment (PPE), and provided training consistent with §1910.132(f).

OSHA's Hazard Communication standard (HCS), 29 CFR §1910.1200, specifically exempts biohazards from coverage [see paragraph (b)(6)(xii)]. Therefore, the training requirements under the HCS do not apply where the material is a biological hazard. If, however, the material is a hazardous chemical that is not exempted by paragraph (b)(6) of the HCS, then the training requirements contained in §1910.1200(h) apply.

The Postal Service describes OSHA requirements and Postal Service procedures and training related to hazardous materials spills in their publication, Hazardous Materials and Spill Response, Handbook EL-812, dated May 1998. In addition, Postal Service Management Instruction EL-810-96-1, Response to Hazardous Materials Releases, describes Postal Service training procedures and requirements for emergency response plans and standard operating procedures. These documents can be downloaded from the Postal Service's website (
http://www.usps.gov) by entering the publication number as a search term.

Thank you for your interest in occupational safety and health. We hope you find this information helpful. Please be aware that OSHA's enforcement guidance is subject to periodic review and clarification, amplification, or correction. Such guidance could also be affected by subsequent rulemaking. In the future, should you wish to verify that the guidance herein remains current, you may consult OSHA's website at
http://www.osha.gov. If you have any further questions, please feel free to contact the [Office of General Industry Enforcement] at (202) 693-1850.


Charles N. Jeffress
Assistant Secretary

[Corrected 02/01/2006]



Footnote(1) As your question involved an electric motor, it is important to note that the electrical standards (in 1910, Subpart S) contain requirements for employee safety relative to electrical hazards in the workplace. The electrical safety-related work practices, §1910.331 through §1910.335, contains provisions (§1910.333(b)) for safeguarding workers (i.e., for lockout and tagging) from the hazards of contacting electrically energized parts. [ Back to text ]





Footnote(2) In accordance with §1910.304(e)(1)(iv), the overcurrent protection devices must be readily accessible to each employee or authorized building management personnel. Caution must be taken not to lock the service panel cabinet and impede employee access to the other operational overcurrent devices. [Thus, if the service panel cabinet is associated with several machines, the lockout device must be affixed in a manner which isolates only the energy associated with the machines(s) that is being serviced or maintained and which does not impede employee access to overcurrent devices associated with machinery that is not affected by the servicing/maintenance activity.] [ Back to text ]