CHM 2045C Lab Safety:

Lab Symbols You Must Know:

toxic       flamableacs









The MSDS web site may be accessed at the following:







In your lab notebook sketch the following HMIS Labeling System and list the descriptions for each number:



Below is a paragraph about the two labeling systems:


“At first glance, the HMISŪ and NFPA labeling systems appear quite similar. Both have four sections colored blue, red, yellow and white. HMISŪ uses colored bars, while NFPA uses colored diamonds. HMISŪ attempts to convey full health warning information to all employees while NFPA is meant primarily for fire fighters and other emergency responders.”

In your lab notebook, the purpose behind the both system and why they are different.

MSDS Relevance

Specific sections of an HMISŪ label include the following:


o    The Health section conveys the health hazards of the material. In the latest version of HMISŪ, the blue Health bar has two spaces, one for an asterisk and one for a numeric hazard rating.

If present, the asterisk signifies a chronic health hazard, meaning that long-term exposure to the material could cause a health problem such as emphysema or kidney damage. NFPA lacks this important information because the NFPA system is meant only for emergency or acute (short-term) exposures.

According to NPCA, the numeric hazard assessment procedure is different than that used by NFPA. Here are the numeric rankings for the HMIS system:


Life-threatening, major or permanent damage may result from single or repeated overexposures.


Major injury likely unless prompt action is taken and medical treatment is given.


Temporary or minor injury may occur.


Irritation or minor reversible injury possible.


No significant risk to health.



For HMIS I and II, the criteria used to assign numeric values (0 = low hazard to 4 = high hazard) are identical to those used by NFPA. In other words, in this category, the systems are identical.

For HMIS III, the flammability criteria are defined according to OSHA standards:


Flammable gases, or very volatile flammable liquids with flash points below 73 °F, and boiling points below 100 F. Materials may ignite spontaneously with air. (Class IA) .


Materials capable of ignition under almost all normal temperature conditions. Includes flammable liquids with flash points below 73 °F and boiling points above 100 °F, as well as liquids with flash points between 73 °F and 100 °F. (Classes IB & IC).


Materials which must be moderately heated or exposed to high ambient temperatures before ignition will occur. Includes liquids having a flash point at or above 100 °F but below 200 °F. (Classes II & IIIA).


Materials that must be preheated before ignition will occur. Includes liquids, solids and semi solids having a flash point above 200 °F. (Class IIIB).


Materials that will not burn.






Reactivity (HMISŪ I and II - now obsolete)

o    The criteria used to assign numeric values (0 = low hazard to 4 = high hazard) were identical to those used by NFPA. In other words, in this category, the systems were identical.

This version is now obsolete. The yellow section has been replaced with an orange section titled Physical Hazards - see the next section for more information.


Physical Hazard (HMISŪ III)

o    Reactivity hazard are assessed using the OSHA criterion of physical hazard. Seven such hazard classes are recognized:

§  Water Reactives

§  Organic Peroxides

§  Explosives

§  Compressed gases

§  Pyrophoric materials.

§  Oxidizers

§  Unstable Reactives

This version replaces the now-obsolete yellow section titled Reactivity - see the previous section for more information. As with the Health and Flammability sections, the level of hazard is indicated using numeric values (0 = low hazard to 4 = high hazard):


Materials that are readily capable of explosive water reaction, detonation or explosive decomposition, polymerization, or self-reaction at normal temperature and pressure.


Materials that may form explosive mixtures with water and are capable of detonation or explosive reaction in the presence of a strong initiating source. Materials may polymerize, decompose, self-react, or undergo other chemical change at normal temperature and pressure with moderate risk of explosion.


Materials that are unstable and may undergo violent chemical changes at normal temperature and pressure with low risk for explosion. Materials may react violently with water or form peroxides upon exposure to air.


Materials that are normally stable but can become unstable (self-react) at high temperatures and pressures. Materials may react non-violently with water or undergo hazardous polymerization in the absence of inhibitors.


Materials that are normally stable, even under fire conditions, and will not react with water, polymerize, decompose , condense, or self-react. Non-explosives.


Personal Protection

o    This is by far the largest area of difference between the NFPA and HMISŪ systems. In the NFPA system, the white area is used to convey special hazards whereas HMISŪ uses the white section to indicate what personal protective equipment (PPE) should be used when working with the material.

Note: The NPCA specifically recommends that "preparers of MSDSs should not place HMISŪ PPE designation codes on the MSDSs or labels that leave the facility, as they do not know the conditions under which their customers use those products." However, these still turn up on some MSDS's.

HMISŪ uses a letter coding system for this section. We at ILPI find this unacceptable because we would rather see the PPE listed explicitly instead of having employees try to remember a bunch of codes or consult a chart, something that could lead to confusion and/or a fatal accident. Likewise, the "custom codes" aspect is particularly dangerous for visitors and contractors who may not remember/recognize that these could vary from job site to job site.

Note: Some of the letters/symbols used in this table are also used as TSCA, CHIP, and/or DoD HMIRS/HCC codes, all of which have completely different meanings and applications! Say, did we tell you we dislike code systems?





We present the lettering scheme here, along with a series of graphics meant to reinforce the meaning of each letter:

HMISŪ Letter

Required Equipment


Safety Glasses


Safety GlassesGloves


Safety GlassesGlovesApron


Full Face ShieldGlovesApron


Safety GlassesGlovesDust


Safety GlassesGlovesApronDust


Safety GlassesGlovesVapor


Safety GogglesGlovesApronVapor


Safety GlassesGlovesDustVapor


Safety GogglesGlovesApronDustVapor


Airline Hood or MaskGlovesFull protective suitBoots

L through Z

Site-specific label. Ask your supervisor or safety specialist for handling instructions