Standard Interpretations

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. Each 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.

1910.119 - What constitutes an emergency response or incidental release of anhydrous ammonia - 10/02/2017
1910.119 - "Applicability of the PSM standard's mechanical intergrity requirements to refinery structures." - 02/01/2010
1910.119 - "Compliance Audits" of the Process Safety Management of Highly Hazardous Chemicals Standard. - 03/21/1995
1910.119 - 1910.119 does not apply to public displays of flame effects. - 05/16/1997
1910.119 - Akzo-Nobel Chemicals - Limits of a Process - 02/28/1997
1910.119 - Applicability of PSM standard to explosive and pyrotechnic manufacturing. - 02/04/1998
1910.119 - Applicability of the Process Safety Management manufacturing processes involving workplace explosives. - 12/30/1993
1910.119 - Applicability of the PSM standard to a flammable liquid manufacturing process. - 07/09/1999
1910.119 - Black liquor recovery boilers, associated oil (or gas) auxiliary fuel burner systems and PSM. - 06/09/1993
1910.119 - Boundaries of a PSM-Covered Process that Includes the Storage of Cylinders of HHCs (Anhydrous Hydrogen Fluoride) - 05/02/2014
1910.119 - Carburization process and the applicability of Process Safety Management for Highly Hazardous Chemicals. - 11/28/1995
1910.119 - Cellulose nitrate and the PSM Standard. - 07/20/1992
1910.119 - Ceramic firing utilizing propane in amounts exceeding 10,000 pounds not subject to process safety management standard. - 08/28/1992
1910.119 - Challenge Testing as a Substitute for Annual Refresher Training. - 11/27/1995
1910.119 - Chlorine storage facility plan and the applicability of the Process Safety Management (PSM) of Highly Hazardous Chemicals Standard. - 08/15/1995
1910.119 - Clarification of "laboratory" and "process" relative to process safety management standard. - 06/24/1992
1910.119 - Clarification of PSM applicability to processes that are based partly or solely on quantities in connected atmospheric storage tanks. - 02/11/2003
1910.119 - Clarification of term "Active Hydrocarbon Zone" as it relates to the oil and gas well drilling operations; and the need to use FRC when performing drilling operations - 10/19/2010
1910.119 - Clarification of the Process Safety Management standard with regard to material and energy balances. - 09/25/1995
1910.119 - Clarification of the term "hydrocarbon" as used in the PSM standard. - 02/04/2013
1910.119 - Clarification on how OSHA would address the use of natural gas or liquid propane gas used in an after-burner to remove volatile organic carbon (VOC) air contaminants. - 02/13/1995
1910.119 - Clarification on terms used in OSHA's PSM standard - 06/23/2023
1910.119 - Clarification on the documentation of inspections and tests required under the mechanical integrity provisions. - 09/16/1996
1910.119 - Clarification on the time allowed for completion of the initial process hazard analysis (PHA) as it may apply to a hypothetical case involving four different work sites of an employer. - 06/01/1995
1910.119 - Clarification on whether flammable liquids used to mix (1) inks used in printing on aluminum foil and paper and (2) paint used in coating aluminum sheets are covered by the PSM standard. - 09/27/1994
1910.119 - Clarification on whether the ozone process described is covered by the PSM Standard. - 10/12/1995
1910.119 - Clarifications of the OSHA standards 1910.109 and 1910.119. - 06/16/1994
1910.119 - Coating processes covered by the PSM standard. - 09/20/1993
1910.119 - Compliance Audits. - 01/05/1995
1910.119 - Confirmation that mixing of liquefied butane, transferred by a CTMV, with gasoline stored in atmospheric tanks at terminals is not covered by the PSM Standard. - 05/17/1995
1910.119 - Coverage under the Process Safety Management Standard. - 03/22/1995
1910.119 - Delivery of hydrogen peroxide, 52% by weight or greater. - 09/08/1993
1910.119 - Determining when a mixture would exceed the threshold quantity in a covered process. - 05/21/2009
1910.119 - Dimethylamine and Anhydrous Dimethlamine and the PSM standard. - 07/09/1993
1910.119 - Documentation methods used to comply with the qualitative evaluation of a range of possible safety/health effects of "failure of controls" requirement of the PSM standard. - 02/01/2005
1910.119 - Electrical hazardous area classification drawings in the workplace. - 12/12/1997
1910.119 - Employee participation requirements of the Process safety management standard. - 01/08/1993
1910.119 - Evaluation of scenarios regarding PSM requirements related to normally unoccupied remote facilities and natural gas processing plants (gas plant). - 02/16/2005
1910.119 - Extent of OSHA's jurisdiction over worksites involving geological and underground storage facilities for gas and hazardous liquids. - 10/07/2008
1910.119 - Flame-resistant and flame-retardant treated clothing for oil and gas well drilling, servicing, and production-related operations - 03/31/2011
1910.119 - Flammable Liquid Processing Letter - 06/04/2018
1910.119 - Formaldehyde (37% by weight or greater) in the Process Safety Management Standard - 06/28/1992
1910.119 - Fumigants used to control insects in food plants. - 05/03/1993
1910.119 - Gasoline used as a fuel to test run inboard and outboard engines does not fall under PSM. - 09/16/1992
1910.119 - HHC standard as it applies to threshold quantity. - 06/01/1994
1910.119 - HHC's as it applies to employer obligation to obtain and evaluate information regarding the contract employer's safety performance and programs - 06/29/1994
1910.119 - HHC's as it applies to exterior, interior tanks. - 06/03/1994
1910.119 - HHC's as it applies to flammable liquid stored at a worksite. - 04/28/1993
1910.119 - HHC's as it applies to pulp and paper industry processes that contain chlorine dioxide - 06/22/1994
1910.119 - HHCs as it applies to end use applications of acrolein. - 12/10/1993
1910.119 - HHCs as it applies to ethylene oxide (ETO). - 12/30/1993
1910.119 - HHCs as it applies to Hydrocarbon fuels used solely for workplace consumption. - 08/19/1993
1910.119 - HHCs as it applies to Hydrogen Peroxide delivered from a tank truck. - 09/09/1993
1910.119 - HHCs as it applies to manufacturing processes involving workplace explosives. - 12/30/1993
1910.119 - HHCs as it applies to storing of flammable liquids. - 06/24/1992
1910.119 - HHCs as it applies to strategic petroleum reserve storage sites. - 12/14/1993
1910.119 - Highly Hazardous Chemical's anhydrous ammonia (NH(3)). - 06/02/1994
1910.119 - Highly Hazardous Chemicals applies to aqueous solutions of Hydrogen Fluoride. - 01/28/1994
1910.119 - Highly Hazardous Chemicals as it applies to "Dowtherm". - 01/26/1994
1910.119 - Highly Hazardous Chemicals as it applies to a covered process. - 03/10/1994
1910.119 - Highly Hazardous Chemicals as it applies to aqueous solutions of hydrofluoric acid. - 05/18/1994
1910.119 - Highly Hazardous Chemicals as it applies to flammable liquid from a stationary tank. - 03/16/1994
1910.119 - Highly Hazardous Chemicals as it applies to operating procedures and certify on an annual basis. - 03/09/1994
1910.119 - Highly Hazardous Chemicals as it applies to solid propellant rocket motors. - 01/31/1994
1910.119 - Highly Hazardous Chemicals as it applies to threshold quantity (TQ) of HHCs. - 04/22/1994
1910.119 - Highly Hazardous Chemicals as it applies to what constitutes the boundaries of a process. - 04/28/1994
1910.119 - Highly Hazardous Chemicals standard, Tertiary Butyl Hydroperoxide (TBHP). - 03/31/1994
1910.119 - Highly Hazardous Chemicals, types of hardware that see contact with explosives. - 05/25/1994
1910.119 - Inspection Guidance for Poultry Slaughtering and Poultry Processing Establishments - [OSH Act of 1970 - Section 5(a)(1)] - 10/28/2015
1910.119 - Interpretation of the Process Safety Management (PSM) of Highly Hazardous Chemicals (HHCs) standard. - 11/14/1994
1910.119 - Interpretation of the Process Safety Management of Highly Hazardous Chemicals Standard. - 09/27/1995
1910.119 - Interpretation of the Process Safety Management of Highly Hazardous Chemicals Standard. - 01/23/1995
1910.119 - Interpretation of the Process Safety Management standard. - 02/03/1993
1910.119 - Is reassembly of a cylinder valve a mechanical integrity activity? - 12/04/2012
1910.119 - Management of Organizational Change - 03/31/2009
1910.119 - Memorandum to Regional Administrators – Process Safety Management Retail Exemption Enforcement Policy - 04/30/2018
1910.119 - Muriatic acid not subject to Process Safety Management standard. - 06/24/1992
1910.119 - Natural gas facility process hazard analysis requirements. - 10/28/1992
1910.119 - Numerous questions related to OSHA's notice to terminate the rulemaking to amend the explosives standard. - 04/24/2012
1910.119 - OSHA enforcement policy of the PSM standard distilleries and related facilities in SIC 2085. - 03/14/2003
1910.119 - OSHA PSM and Explosives Standards as They Relate to the DOT Classification "Not in the Explosive Class" - 03/17/2021
1910.119 - OSHA's approval of the Zurich Hazard Analysis, as an appropriate method for conductiong the process hazard analysis which is required by 1910.119. - 07/26/1995
1910.119 - OSHA's Standard Process Safety Management of Highly Hazardous Chemicals. - 12/07/1995
1910.119 - Outer Continental Shelf lands--OSHA and the U.S. Coast Guard. - 02/02/1993
1910.119 - Pressure vessels used at oil and gas extraction/production facilities and applicability of 29 CFR 1910.106 - 07/17/2006
1910.119 - Process safety information for ventilation system design. - 12/22/2003
1910.119 - Process Safety Management - Threshold quantity is determined on the amount of HHC in the process. - 07/18/1994
1910.119 - Process Safety Management (PSM) of Highly Hazardous Chemicals standards, as it may apply to processes containing HHCs. - 02/22/1995
1910.119 - Process safety management at what point a work site change would no longer be considered a modification but a new facility. - 01/11/1996
1910.119 - Process Safety Management of Highly Hazardous Chemicals and Covered Concentrations of Listed Appendix A Chemicals - 07/21/2016
1910.119 - Process Safety Management of Highly Hazardous Chemicals and process hazard analyses. - 10/31/1996
1910.119 - Process Safety Management of Highly Hazardous Chemicals as it may apply to more than 250 pounds thionyl chloride stored on your work site. - 09/27/1994
1910.119 - Process Safety Management of highly hazardous chemicals standard. - 08/16/1996
1910.119 - Process Safety Management of Highly Hazardous Chemicals. - 11/30/1994
1910.119 - Process Safety Management Program required by OSHA. - 02/06/1995
1910.119 - Process Safety Management Standard. - 12/02/1994
1910.119 - Processes involving workplace explosive. - 12/30/1993
1910.119 - Production facilities that recover natural gas liquids may have enforceable PSM-covered processes - 12/19/2018
1910.119 - Propane as a fuel for ovens; Chlorine storage exceeding 1500 pounds. - 04/14/1993
1910.119 - PSM and Aerosol (Flammable Gas) Containers Stored in Warehouses/Distribution Centers - 06/28/2019
1910.119 - PSM and large batch-mixing tanks - 03/19/2012
1910.119 - PSM applicability to warehousing flammable liquids and other HHCs. - 02/01/2002
1910.119 - PSM clarification on flammable lubrication in aerosol cans, to prevent foods from sticking to heated cookware - 10/04/1994
1910.119 - PSM compliance for ammonia refrigeration systems. - 07/12/2006
1910.119 - PSM Coverage of LNG Facilities - 04/27/2021
1910.119 - PSM coverage of utility systems; whether 1910.269 preempts the PSM standard for power generation facilities that serve covered processes. - 01/31/2008
1910.119 - PSM for pharmaceutical plant - 03/05/2012
1910.119 - PSM Standard does not apply to 10,000 pounds of hydrocarbon fuel on site used solely as a fuel for a furnace. - 10/22/1992
1910.119 - PSM threshold quantity; EPA regulated and permitted RCRA Hazardous waste treatment. - 12/21/1992
1910.119 - RAGAGEP in Process Safety Management Enforcement - 05/11/2016
1910.119 - Recognized and Generally Accepted Good Engineering Practices in Process Safety Management Enforcement - 05/11/2016
1910.119 - Refresher training requirements. - 05/28/1993
1910.119 - Regarding "Compliance Audits" of the Process Safety Management for Highly Hazardous Chemicals Standard. - 02/24/1995
1910.119 - Remote distance, close proximity and other PSM questions. - 02/15/1994
1910.119 - Requirement for flame-resistant clothing in petrochemical plant covered by PSM. - 03/07/2006
1910.119 - Response regarding the application of the OSHA Process Safety Management Standard to utility LPG distribution facilities. - 11/19/1996
1910.119 - Sodium Azide as Used in the Manufacturing Process of Automobile Air Bags. - 06/30/1997
1910.119 - Solutions of hydrogen chloride in water do not apply to Process Safety Management Standard. - 01/21/1993
1910.119 - Steam boilers fired by flammable liquids or natural gas and the PSM standard. - 01/08/1993
1910.119 - Storage of flammable liquids and the applicability to the Process Safety Management standard. - 09/11/1995
1910.119 - Storage of flammable liquids and the PSM. - 06/04/1992
1910.119 - Sulfuric acid and the PSM standard. - 06/24/1993
1910.119 - The (PSM) for Highly Hazardous Chemicals Standard and its applicability to the specific scenarios outlined. - 10/25/1995
1910.119 - The Ciba Self-Medication, Inc. (CSM) facility and the application of OSHA's PSM of Highly Hazardous Chemicals Standard. - 09/07/1995
1910.119 - The Process Safety Management (PSM) of Highly Hazardous Chemicals (HHC) standard. - 07/11/1994
1910.119 - The Process Safety Management Standard. - 04/29/1997
1910.119 - The term "interconnection" as it would apply to utilities, steam and electric, used in a covered process. - 09/14/1995
1910.119 - The use of natural gas or liquid propane gas used in an after-burner. - 02/23/1995
1910.119 - Three scenarios and questions regarding on-site natural gas in pipe lines used as a fuel and as a feed stock. - 09/14/1995
1910.119 - Training requirements for mechanics repairing and/or testing pressure relief devices. - 02/04/2013
1910.119 - Training requirements of PSM. - 10/09/1992
1910.119 - Use of ANSI/ISA S84.00.01-2004 Parts 1-3 (IEC 61511 MOD) to comply with OSHA's Process Safety Management standard - 11/29/2005
1910.119 - Various questions on OSHA standards - 09/01/1992
1910.119 - Voluntary safety and health audits under the Occupational Safety and Health Act - 09/11/1996
1910.119 - When steam boilers fired by flammable liquids or natural gas are subject to the PSM standard. - 01/18/1993
1910.119 - Worker protection for employees incinerating hazardous waste on cement plant property. - 05/15/1996
1910.119 - Written operating procedures for computerized process control and safety interlock system software. - 09/21/1992
1910.119(a) - Application of Process Safety Management of Highly Hazardous Chemicals to the manufacture of explosives and pyrotechnics. - 06/15/1992
1910.119(a) - OSHA PSM and Explosives Standards as They Relate to the DOT Classification "Not in the Explosive Class" - 03/17/2021
1910.119(a) - OSHA will not enforce the PSM standard at oil and gas production facilities. - 04/11/2000
1910.119(a) - Process Safety Management (PSM) applicability to liquid petroleum gas (LPG) bottle filling process. - 03/14/2000
1910.119(a) - Production facilities that recover natural gas liquids may have enforceable PSM-covered processes - 12/19/2018
1910.119(a) - PSM and Aerosol (Flammable Gas) Containers Stored in Warehouses/Distribution Centers - 06/28/2019
1910.119(a) - Storage of pre-charged air conditioners and heat pumps in warehouses or distribution centers - 06/06/2024
1910.119(a)(1) - Applicability of PSM standard to on-site use of methane as fuel. - 09/21/2000
1910.119(a)(1)(i) - PSM coverage of utility systems; whether 1910.269 preempts the PSM standard for power generation facilities that serve covered processes. - 01/31/2008
1910.119(a)(1)(ii) - Determining when a mixture would exceed the threshold quantity in a covered process. - 05/21/2009
1910.119(a)(1)(ii) - PSM coverage of utility systems; whether 1910.269 preempts the PSM standard for power generation facilities that serve covered processes. - 01/31/2008
1910.119(a)(1)(ii) - PSM for pharmaceutical plant - 03/05/2012
1910.119(a)(1)(ii)(A) - Thomas' MAPP gas glass mold heat processes fall within the PSM hydrocarbon fuels exemption. - 12/08/2000
1910.119(a)(1)(ii)(B) - Applicability of the PSM standard to a flammable liquid manufacturing process. - 07/09/1999
1910.119(a)(1)(ii)(B) - Clarification of PSM applicability to processes that are based partly or solely on quantities in connected atmospheric storage tanks. - 02/11/2003
1910.119(a)(1)(ii)(B) - Coverage of Stored Flammables Under the Process Safety Management Standard. - 05/12/1997
1910.119(a)(1)(ii)(B) - OSHA enforcement policy of the PSM standard distilleries and related facilities in SIC 2085. - 03/14/2003
1910.119(a)(1)(ii)(B) - PSM applicability to warehousing flammable liquids and other HHCs. - 02/01/2002
1910.119(a)(1)(ii)(B) - Riggs – PSM Coverage of Biodiesel Facilities - 09/26/2008
1910.119(a)(2)(ii) - Extent of OSHA's jurisdiction over worksites involving geological and underground storage facilities for gas and hazardous liquids. - 10/07/2008
1910.119(a)(2)(iii) - PSM Standard exemption for "normally unoccupied remote facilites" (water treatment plant). - 05/29/1998
1910.119(b) - Determining when a mixture would exceed the threshold quantity in a covered process. - 05/21/2009
1910.119(b) - Evaluation of scenarios regarding PSM requirements related to normally unoccupied remote facilities and natural gas processing plants (gas plant). - 02/16/2005
1910.119(b) - Extent of OSHA's jurisdiction over worksites involving geological and underground storage facilities for gas and hazardous liquids. - 10/07/2008
1910.119(b) - OSHA Interpretation on Connected System 29 CF 1910.119(b) - 02/15/2017
1910.119(b) - Production facilities that recover natural gas liquids may have enforceable PSM-covered processes - 12/19/2018
1910.119(b) - PSM applicability to warehousing flammable liquids and other HHCs. - 02/01/2002
1910.119(b) - PSM coverage of utility systems; whether 1910.269 preempts the PSM standard for power generation facilities that serve covered processes. - 01/31/2008
1910.119(d)(3) - "Applicability of the PSM standard's mechanical intergrity requirements to refinery structures." - 02/01/2010
1910.119(d)(3) - Compliance with PSM and ANSI/ISA-S84.01 for safety instrumented systems - 03/23/2000
1910.119(d)(3)(i) - Process safety information for ventilation system design. - 12/22/2003
1910.119(d)(3)(i) - PSM compliance for ammonia refrigeration systems. - 07/12/2006
1910.119(d)(3)(ii) - PSM and Aerosol (Flammable Gas) Containers Stored in Warehouses/Distribution Centers - 06/28/2019
1910.119(d)(3)(ii) - PSM compliance for ammonia refrigeration systems. - 07/12/2006
1910.119(d)(3)(iii) - Determination of safety for existing process equipment is required prior to start-up. - 01/30/2001
1910.119(d)(3)(iii) - Recalculating pressure vessel design; codes "no longer in use." - 03/05/1998
1910.119(e) - "Applicability of the PSM standard's mechanical intergrity requirements to refinery structures." - 02/01/2010
1910.119(e) - Applicability of the PSM standard to a flammable liquid manufacturing process. - 07/09/1999
1910.119(e) - Documentation methods used to comply with the qualitative evaluation of a range of possible safety/health effects of "failure of controls" requirement of the PSM standard. - 02/01/2005
1910.119(e)(1) - Clarification of requirements for storage and use of flammable and/or combustible liquids. - 12/26/2007
1910.119(e)(3) - Documentation methods used to comply with the qualitative evaluation of a range of possible safety/health effects of "failure of controls" requirement of the PSM standard. - 02/01/2005
1910.119(e)(3) - PSM compliance for ammonia refrigeration systems. - 07/12/2006
1910.119(e)(3) - Steps for updating and revalidating a Process Hazard Analysis (PHA). - 01/22/1998
1910.119(e)(4) - Process hazard analysis facilitator's training requirements. - 11/19/2001
1910.119(e)(5) - Documentation of PHA Findings and Recommendations - 10/02/2020
1910.119(e)(6) - Steps for updating and revalidating a Process Hazard Analysis (PHA). - 01/22/1998
1910.119(e)(6) - Updates to PHA Extended Shutdown Facility - 09/20/2019
1910.119(e)(7) - Documentation of PHA Findings and Recommendations - 10/02/2020
1910.119(f)(1)(iii)(B) - Requirement for flame-resistant clothing in petrochemical plant covered by PSM. - 03/07/2006
1910.119(f)(1)(iv) - Compliance with PSM and ANSI/ISA-S84.01 for safety instrumented systems - 03/23/2000
1910.119(f)(4) - Requirements for the control of personnel entering a facility under the Process Safety Management standard. - 03/16/2005
1910.119(h)(2) - Requirement for flame-resistant clothing in petrochemical plant covered by PSM. - 03/07/2006
1910.119(h)(2)(iv) - Requirements for the control of personnel entering a facility under the Process Safety Management standard. - 03/16/2005
1910.119(h)(2)(vi) - Employer Responsibilities and Contractor Responsibilities under the PSM Standard - 02/16/2022
1910.119(h)(3) - Applicability of PSM standard to on-site use of methane as fuel. - 09/21/2000
1910.119(h)(3) - Employer Responsibilities and Contractor Responsibilities under the PSM Standard - 02/16/2022
1910.119(h)(3) - Requirement for flame-resistant clothing in petrochemical plant covered by PSM. - 03/07/2006
1910.119(j) - "Applicability of the PSM standard's mechanical intergrity requirements to refinery structures." - 02/01/2010
1910.119(j) - Compliance with PSM and ANSI/ISA-S84.01 for safety instrumented systems - 03/23/2000
1910.119(j)(1) - PSM coverage of utility systems; whether 1910.269 preempts the PSM standard for power generation facilities that serve covered processes. - 01/31/2008
1910.119(j)(2) - Requirement for flame-resistant clothing in petrochemical plant covered by PSM. - 03/07/2006
1910.119(j)(4)(iv) - Is reassembly of a cylinder valve a mechanical integrity activity? - 12/04/2012
1910.119(j)(6)(i) - PSM compliance for ammonia refrigeration systems. - 07/12/2006
1910.119(j)(6)(ii) - PSM compliance for ammonia refrigeration systems. - 07/12/2006
1910.119(k) - Sulfur sticks and hot work requirements - 04/30/2024
1910.119(k)(2) - PSM compliance for ammonia refrigeration systems. - 07/12/2006
1910.119(l) - "Applicability of the PSM standard's mechanical intergrity requirements to refinery structures." - 02/01/2010
1910.119(l)(2)(i) - PSM compliance for ammonia refrigeration systems. - 07/12/2006
1910.119(l)(4) - PSM compliance for ammonia refrigeration systems. - 07/12/2006
1910.119(l)(5) - PSM compliance for ammonia refrigeration systems. - 07/12/2006
1910.119(m)(3) - PSM compliance for ammonia refrigeration systems. - 07/12/2006
1910.119(n) - Requirements for emergency response and planning under the Process Safety Management Standard. - 06/24/2003
1910.119(n) - Requirements for the control of personnel entering a facility under the Process Safety Management standard. - 03/16/2005
1910.119(o) - PSM applicability to warehousing flammable liquids and other HHCs. - 02/01/2002
1910.119(o)(1) - PSM compliance for ammonia refrigeration systems. - 07/12/2006

OSH Act - Section 5(a)(1)