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Joint OSHA/Health Canada Guidance on Labeling Pictogram

for Hazards Not Otherwise Classified (HNOC), Physical Hazards 

Not Otherwise Classified (PHNOC) and Health Hazards Not 

Otherwise Classified (HHNOC)

As part of a commitment made under the 2016-17 Regulatory Cooperation Council (RCC) work plan for 

workplace chemicals that “Canada and the U.S. will continue to prevent and reduce variances, while 

respecting the legislative and regulatory requirements of each country and without reducing or 

compromising worker health and safety,” Canada and the U.S. have agreed to develop joint guidance on 

how the pictogram requirements for Hazards Not Otherwise Classified (HNOC), Physical Hazards Not 

Otherwise Classified (PHNOC) and Health Hazards Not Otherwise Classified (HHNOC) can be met in 

compliance with each country’s implementation of the GHS.

The definition of “hazardous chemical” in paragraph (c) of the Occupational Safety and Health 

Administration’s (OSHA’s) Hazard Communication Standard (HCS) 2012 (29 CFR 1910.1200) includes any 

chemical which is classified as an HNOC. Paragraph (c) of the HCS defines HNOC as “an adverse physical 

or health effect identified through evaluation of scientific evidence during the classification process that 

does not meet the specified criteria for the physical and health hazard classes.... This does not extend 

coverage to adverse physical and health effects for which there is a hazard class addressed [in the 

standard], but the effect either falls below the cut-off value/concentration limit of the hazard class or is 

under a GHS hazard category that has not been adopted by OSHA (e.g., acute toxicity Category 5).”

Health Canada’s Hazardous Products Regulations (HPR) includes PHNOCs

1

and HHNOCs

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as distinct 

hazard classes. The PHNOC hazard class and the HHNOC hazard class cover physical and health hazards, 

respectively, that are not covered by any other physical or health hazard classes in the HPR. OSHA’s HCS 

does not differentiate between physical and health hazards not otherwise classified.

OSHA’s HCS does not require label elements for HNOCs, whereas under the HPR, label elements are 

required for PHNOCs and HHNOCs. OSHA’s HCS Directive (Inspection Procedures for the Hazard 

Communication Standard, CPL 02-02-079, dated July 9, 2015) includes guidance allowing the chemical 

manufacturer, importer, or distributor to include hazard symbols on the label or safety data sheet (SDS)

for HNOCs as long as that symbol is not an HCS pictogram and does not contradict or cast doubt on the 

information that is required. However, OSHA provided clarification to this in the September 21, 2016,

field enforcement memorandum to permit the use of the exclamation mark pictogram for HNOCs.

 

1 Physical hazard not otherwise classified means a physical hazard presented by a product, mixture, material, or substance that 

is different from any other physical hazard addressed by any other Subpart in this Part and that has the characteristic of 

occurring by chemical reaction and resulting in the serious injury or death of a person at the time the reaction occurs

(http://laws-lois.justice.gc.ca/PDF/SOR-2015-17.pdf).

2 Health hazard not otherwise classified means a health hazard presented by a mixture or substance that is different from any 

other health hazard addressed by any other Subpart in this Part and that has the characteristic of occurring via acute or 

repeated exposure and having an adverse effect on the health of a person exposed to it, including an injury, or resulting in the 

death of that person (http://laws-lois.justice.gc.ca/PDF/SOR-2015-17.pdf). 
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Health Canada and OSHA have agreed that the exclamation mark pictogram is an appropriate symbol for 

the HNOC, HHNOC, and PHNOC classifications. OSHA will permit the use of the exclamation mark 

pictogram for HNOCs if the label also indicates that the pictogram is being used for a hazard not 

otherwise classified (e.g., the words “Hazard Not Otherwise Classified” or “HNOC” must appear below 

the exclamation mark pictogram). For other hazard classes, the name of those hazard classes is not 

required to be provided below the pictogram(s). In Canada, no acronym (including “HHNOC” or 

“PHNOC”) is required to appear below the exclamation mark pictogram. Nonetheless, Canada allows 

the acronym “HNOC” or the statement “Hazards Not Otherwise Classified” to appear below the 

exclamation mark pictogram on a label.

The exclamation mark pictogram may appear only once on a label; if it already appears as a required 

pictogram, it may not appear a second time as supplemental information for the HNOC. OSHA considers 

the exclamation mark pictogram to be acceptable for HNOCs because it conveys more general hazard 

information and does not contradict or cast doubt on the information that is required. Health Canada

has agreed that the use of the exclamation mark pictogram is acceptable for PHNOCs and HHNOCs, and 

meets the requirements to use an appropriate pictogram in all cases.
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Annex: Example

The following provides an example of a hazardous product that is classified as HNOC (in the U.S.) and 

PHNOC (in Canada), and another physical hazard class (in both countries) that does not require the 

exclamation mark pictogram. For the purposes of this example, the hazardous product is classified as 

the following: 

Under HCS, Flammable Liquids—Category 1 and HNOC;

Under the HPR, Flammable Liquids—Category 1 and PHNOC—Category 1

The illustration below shows how the HNOC/PHNOC pictogram can be displayed in a way that is 

acceptable in both the U.S. and Canada:

HNOC

Danger

Extremely flammable liquid and vapor

Appropriate hazard statement for the PHNOC3

Appropriate precautionary statements for 

Flammable Liquids—Category 1 and PHNOC3 

 

3 OSHA’s HCS does not require hazard or precautionary statements for HNOCs.