By David Gecic
Hazardous chemicals are common in the metal finishing, industrial painting, and plating industry. Cleaners, metal treatments, paint thinners, and rust preventatives are examples. The hazards could be corrosive, flammable, or otherwise dangerous. The descriptions show up on drums, labels, bill-of-ladings, and other documents. Regulations that produce them are for shipping purposes only but can still give us valuable information about a product.
Some examples of these descriptions are:
UN-1760, Cleaning Compound n.o.s. (phosphoric acid), 8, III
UN1260, Petroleum Product nos, (Naphtha petroleum, heavy alkylate), 3, PG III
UN-1230, Gasoline, Flammable Liquid, 3, PG II
UN-1791, Hypochlorite Solution, 8, PG III, ERG=154
These all have information in a certain order required by Department of Transportation (DOT) regulations. The regulations are found in chapter 49 of the Code of Federal Regulations. There are several different parts to each hazardous description and each gives a certain amount of information. Let’s look at the different parts.
UN Identification Number
Each hazardous substance is assigned a number beginning with “UN” by an organization called The United Nations Committee of Experts on the Transport of Dangerous Goods. The US Department of Transportation also assigns numbers and these begin with “NA”. There is a move to phase out NA numbers and they will probably not be allowed some time in the future. Currently, there is a preference to use the UN numbers. NA signifies North America, however both Canada or Mexico require the UN designation already and the US is the only county that still allows their use.
There are UN designations for everything from explosive mines to paint thinner to oxygen cylinders. Any hazardous material they can think of they have given a number to.
Proper Shipping Name
Following the UN number there will be a description of what the material is. Sometimes this description will be a generic description such as “Cleaning Compound” or “Corrosive Liquid” or even “desensitized Explosive”. But usually in a pure substance or a substance where the primary hazard is from a single ingredient it will only list that ingredient. There are approved names for the substances and the approved name must be used.
Some descriptions have the letters “NOS” or “nos” or “n.o.s.” after them. This stands for Non-Otherwise-Specified. Almost all of these cases require the name of the ingredient that makes the material hazardous surrounded by parenthesis.
Hazard Class
The hazard class is one of the more important numbers in the shipping description. It describes the actual hazard of the material. Some classes have sub-classes but you will not normally run in to them in most industrial applications. For example, hazard class 1.1 describes an explosive that explodes all at once, and hazard class 1.2 describes explosives that have a projectile hazard. If there is more than one health hazard the secondary one (in parenthesis) follows the primary one.
A summary of the hazard classes with an emphasis on industrial applications are: 1) Explosives, 2.1) Flammable Gases, 2.2) Compressed Gases, 2.3) Poisonous Gases, 3) Flammable Liquids, 4.1) Flammable Solids, 4.2) Spontaneously Combustible Material, 4.3) Dangerous When Wet Material, 5) Oxidizers, 6.1) Poisonous Material, 6.2) Infectious Material, 7) Radioactive Materials, 8) Corrosive Materials, 9) Miscellaneous hazards. Each one is subject to different shipping regulations.
The most commonly encountered hazard groups for metal finishing and coating will be: Class 3) Flammable Liquids, and Class 8) Corrosive Materials.
Packing Group
The packing group is either Roman numeral I, II, or III. This describes the relative hazard of the material with “I” being the most hazardous and “III” being the least hazardous. Often the concentration of the material in the product will determine what number will be assigned to the product.
Emergency Response Guide (optional)
The Emergency Response Guide is a common book used by fire department and shippers to describe the procedures needed in case of a spill or other emergency. It is often abbreviated ERG. It is not required by any DOT regulations but is often included as additional information. A shipment must include either a Safety Data Sheet (SDS) or a ERG number.
Class 3: Flammable Liquids
Paint thinners, many paint strippers, and many solvent cleaners fall into this category. Again, many common substances are also in this category. Gasoline, lighter fluid, and rubbing alcohol are all in this category. The higher the number is the less flammable it is. “Flammable” does not mean the product will not burn, it means that the fumes will not ignite easily. Although there are some exceptions it usually means a material that has a flash point if less than 140 degrees F. Some material with flash points above 100 degrees F can be classified as combustible rather than hazardous for domestic shipping only.
This Class is divided into packing groups based on the flash point of the material. A product is Packing Group I is very volatile and very dangerous. It BOILS at a temperature below 95 degrees F and has flammable fumes. Packing Group II is more common and contains products with flash points below 73 degrees F. Packing Group III is between 73 and 140 degrees F.
Class 5: Oxidizers
An oxidizer can present an additional fire hazard because in the case of a fire these materials will create their own oxygen and will be hard to extinguish. They also may combine with other materials and create a hazardous or explosive mixture. Concentrated bleach and hydrogen peroxide are common oxidizer chemicals. Some material labelled as an oxidizer however may present very little hazard.
Class 6: Poisonous Materials
A quick note on poisonous materials. Many materials will be poisonous and corrosive or poisonous and flammable at the same time. Some products may have a major corrosive component and a minor poison component. These products may be poisonous by ingestion but be so corrosive that the poison risk will never occur because the product would not be able to be swallowed. It may sound dangerous but often these products will never be ingested so the poison hazard is not really applicable. But sometimes a material may be labelled as an “Inhalation Poison” also and some of these can be very dangerous.
Class 8: Corrosive Materials
This class of chemicals is very common in the metal finishing industries. Many cleaners, metal treatments, brighteners, and plating chemicals fall into this class. Any strong acid or alkaline material falls into this class. It does not distinguish whether it is acidic or basic. It focuses on its danger to human health. Many common substances fall into this category for example bleach and Drano drain cleaner.
The definition of corrosive is officially: “a liquid or solid that causes full thickness destruction of human skin at the site of contact” also a material that: “has a severe corrosion rate on steel or aluminum”. Depending on the time it takes to destroy your skin it is classified as Packing Group I, II, or III. The higher the number is the less corrosive it is. This is the definition of corrosive as of early March 2019. Soon the US DOT may be moving to the UN definition of corrosive which is “irreversible damage to the skin” to this corresponds closer to the definition on SDS sheets. On an SDS skin damage is considered irreversible while skin irritation is considered reversible.
If a product causes skin irritation or may cause an allergic reaction it is not considered corrosive. If a product causes skin sensitization or long-term exposure causes problems it also is not considered corrosive. But these are outlined in the SDS.
What This All Means in the Workplace
The SDS is the official document that describes the safety and health hazards of a material but the shipping description also has valuable information. Specifically, you can look at the Roman numeral in the description and the lower the number the more hazardous it will be.
The most common materials in metal finishing are in Class 3: Flammable and Class 8: Corrosive.
If a material is a Class 3: Flammable and in Packing Group: I than it has more hazards than other flammable or combustible material in Packing Group II or III. If it is Class 3, it may have special local storage requirements due to fire hazards.
Class 8: Corrosive materials are hazardous from skin contact or inhalation of spray or mist. They usually don’t have hazardous fumes. They may and that would be in the SDS.
A material marked Class 6) Poisonous material may only be poisonous if ingested. It may not be a major hazard the way it is used in the workplace. Again, the SDS would explain their hazards better.
A shipping label that indicates “Inhalation Hazard” probably requires extra precautions and safety concerns.
Oxidizers Class 5) may need to be stored separately because of fire hazards. That is dependent on local fire codes.
At Home
If you look under your sink at home, in your kitchen, and your medicine cabinet, you will find many hazardous materials. Floor cleaners, bleach, wax strippers, ammonia, drain cleaners, medicines, rubbing alcohol, some consumable alcohols, toilet bowl cleaners, corn starch, insect repellent, shaving cream, hydrogen peroxide, paint thinner, some oil-based paints, hair coloring, anti-aging products, perfume, and many other materials are potentially hazardous from a DOT standpoint. From an OSHA or EPA standpoint the list is even longer.
Usually the only reason you can have them in your house is that they are in a limited quantity or a certain concentration that allows them to be used. Because of this you were able to transport them from the store to your house. A larger container or a higher concentration of them would require shipment by a certified hazardous shipper with warning labels on the side of their truck. They would also require special documented training before use.
Read all the labels and Safety Data Sheets on all the products you use. Ask questions, and stay safe.
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