A REVIEW OF:  THE HAZARD COMMUNICATION STANDARD

The purpose of a Hazard Communication Program is to help employees understand the potential hazards of chemicals that used in their workplace. This training, required by the Occupational Safety & Health Act, is also called Workers' Right To Know. Failure to meet all the requirements of this law (29 CFR 1910.1200) is OSHA's most frequently cited violation. One of the reasons for this is, many employers, supervisors and workers think chemicals are just too complex to explain and to understand. As a result, there is a temptation to avoid the subject.

Hazard Communication is very important, however, because it can protect employees from dangers that may be present when chemicals are being used. One very important key to a Hazard Communication Program is the Material Safety Data Sheet. These sheets tell you "everything you need to know" about a specific chemical. If you read the MSDS you will be able to determine:

The HEALTH HAZARDS associated with any chemical you are using or are exposed to;
How FLAMMABLE the product is, and at what temperature it may ignite;
The REACTIVITY of the chemical with water or other agents-will it explode, etc.?
What PERSONAL PROTECTIVE EQUIPMENT (PPE) is needed to work with the product.

Exposure Limits:

PEL = Permissible Exposure Limit (OSHA regulated): A concentration of a chemical that a worker can be exposed to during an 8 hour day with no adverse health effects. Expressed as ppm = parts per million and mg/m3 = milligrams per meter cubed.

TLV = Threshold Limit Value (ACGIH recommended): A concentration of a chemical that a worker can be exposed to during an 8 hour day with no adverse health effects. Expressed as ppm = parts per million and mg/m3 = milligrams per meter cubed.

REL = Recommended Exposure Limit (NIOSH recommended): A concentration of a chemical that a worker can be exposed to during an 8 hour day with no adverse health effects. Expressed as
ppm = parts per million and mg/m3 = milligrams per meter cubed.

IDLH = Immediately Dangerous to Life and Health

TWA = Time Weighted Average.

STEL = Short Term Exposure Limit

Physical Characteristics of Chemicals

Vapor Density = A term used to describe the weight of a vapor as compared to the air. This is a number that is relative to air, where air = 1. If the number is greater than 1 the vapor is heavier than air and will sink. When the number is less than 1 the vapor is lighter than air and will rise.

Specific Gravity = A term used to describe the weight of a substance as compared to water. This is a number that is relative to water, where water = 1. If the number is greater than 1 the substance is heavier than water and will sink. When the number is less than 1 the substance is lighter than water and will float.

pH = This is a measure of a chemical alkalinity or acidity (acid or base). It is based on a scale of 1 to 14 where 7 is neutral. The scale is based on a factor of 10. The numbers that are less than 7 are acids and the numbers that are greater than 7 are bases. So a chemical with a pH of 6 is 10 times more acid than neutral and a chemical with a pH of 5 is 100 times more acid.

Boiling Point = The temperature at which a liquid will turn to a vapor. Water boils at 212 degrees F.

Flammable Characteristics of Chemicals:

Flashpoint = The temperature above which a chemical will give off sufficient vapors so if exposed to an ignition source can explode. The flashpoint of gasoline is –45 degrees F. At temperatures above this gasoline will give off vapors. Diesel Fuel has a flashpoint of 125 degrees F, this means it has to be very hot for diesel fuel to give off sufficient vapors to ignite.

LEL and UEL = Lower Explosive Limit (LEL), Upper Explosive Limit (UEL) These are terms used to describe the range in concentration where flammable vapors have mixed in the air and are explosive. So if a chemical has a LEL of 2 and a UEL of 5 it means that when 2% of the air is comprised of the chemical it can explode up to the point where there is 5% present. Below 2% it is to lean to burn, above 5% it is to rich to burn.

Autoignition = The temperature at which a substance will ignite automatically. It does not need an ignition source the temperature alone is sufficient to cause combustion.

Labels  (NFPA 704)

HEALTH HAZARD:

4-  EXTREME: Highly toxic may be fatal on short term exposure. Special protective equipment required.

3-  SERIOUS : Toxic - avoid inhalation or skin contact.

2- MODERATE: Moderately toxic - may be harmful if inhaled or absorbed.

1- LIGHT : Slightly toxic - may cause slight irritation.

0- MINIMAL: All chemicals have some degree of toxicity.

FLAMMABILITY HAZARD:

4- EXTREME: extremely flammable gas or liquid, flash point below 73o F

3- SERIOUS : Flammable -flash point 73 o F. to 100o F.

2- MODERATE: Combustible-requires moderate heating to ignite. Flash point 100o F. to 200o F.

1- LIGHT : Slightly combustible - requires strong heating to ignite.

0- MINIMAL: Will not burn under normal conditions.

REACTIVITY HAZARD:

4- EXTREME: Explosive at room temperature.

3- SERIOUS: May explode, if shocked, heated under confinement or mixed with water.

2- MODERATE: Unstable, may react with water.

1- LIGHT : May react if heated or mixed with water.

0- MINIMAL: Normally stable, does not react with water.


Every employee should be able to answer, and should remember, the following questions:

Where are the MSDS's kept for the chemicals I am exposed to?
What kinds of hazards do I face when I use-or misuse--a given chemical?
Do I understand the emergency procedures to follow in the event of a spill?
Have I inspected my personal protective equipment to be sure that it will protect me properly when and if I need to use it?

A convenient tool for reviewing the hazards and control of chemicals in your operation is an MSDS Information Review form. Critical information can be transferred to this form and most people find it more "user friendly" than the full Material Safety Data Sheet. The complete MSDS can be reviewed when more specific details are needed, and should always be available.

Sample MSDS

Training Roster

Employee Training Acknowledgement