Physical Hazards:
Thermal
Thermal hazards include both cool, and hot hazards. Cold hazards cover cryogenic materials and some compressed gases that under compression become liquids. These materials can flash freeze tissues and cause intense burning and stinging pains. Hot hazards are simply just too hot for organic tissues to bear and result in burns. Hot hazards are commonly found in manufacturing environments where taking raw materials and reshaping it to a specific form takes place. Such environments include steel manufacturing, plastics molding, and glass working. Cold hazards are usually found in similar industries as cryogenic materials are used to quickly cool the hot materials so they hold their shape, or to reinforce the material's strength.
Slips, Trips, Falls, and Crushing
Slips, trips, falls, and crushing hazards often do not have much to do with the interactive properties of materials with other chemicals, but rather how they are handled. Crush hazards specifically are more closely related to storage of chemicals in drums and can be reduced by using padded gloves, and avoiding stacking of drums. Slips, trips and falls can mostly be avoided by good housekeeping practices, and attention to debris created during a manufacturing process such as grinding. In some instances, simple interactions can cause cryogenic materials to pose a slip hazard because the cool air can condense on the floor and leave water droplets or even puddles. An example of this is in deflashing processes for rubber products where liquid nitrogen is used to flash freeze the rubber so that the "flashing", or extra bits of rubber left over from the molds, can be easily removed.
Reaction Hazards:
Oxidizers
Oxidizers are substances that cause, or improve combustion of other materials. Strong oxidizers release large quantities of oxygen through chemical decomposition. some oxidizers can be found in household locations because even hydrogen peroxide is considered an oxidizer. In consumer concentrations (1% usually) it is a weak oxidizer, but in commercial settings, it can be a much higher concentration. Other oxidizers may not contain oxygen, but rather halogens such as fluorine and bromine. Oxidizers can lower the flash point, lower explosive limit, and autoignition temperature while also raising the upper explosive limit of materials.
Corrosives
Acids and bases make up a vast proportion of hazardous materials, which means that corrosive hazards are very prevalent in the EHS field. Handling corrosives can require special PPE such as PVC gloves, goggles, aprons, and sometimes full body suits. The amount and type of PPE required when working with various corrosives is usually determined by the chemical's pH value. Very strong acids have very low pH values of 1 or 2, whereas very strong bases have high pH's between 13 and 14. Some corrosives such as sulfuric acid and nitric acid act as oxidizers as well as possessing corrosive properties. This can lead them to be much more destructive to the body and they should be handled with much care and caution.
Chemical Incompatibility
Some materials are safe to work with, so long as they have not been mixed with other chemicals. Water is a major player in incompatibility, especially with chlorinated substances and their byproducts. Combining water with some of these chlorides can generate and release toxic gases, cause ignition and fire, and even explode.
Environmental Hazards:
Bioaccumulating
Bioaccumulation is a way of describing what happens when a chemical is left unchanged in the environment and then compound on themselves to the point that they can become toxic. Examples of bioaccumulating substances include heavy metals such as lead and mercury, as well as chlorinated substances like PCB's. Many of the chemicals that have a tendency to bioaccumulate in tissues, attach themselves to target organs. Lead attacks the brain along with mercurym but in different ways. PCB's and other chlorinated substances tend to accumulate in fat tissues which allows them to compund in animals and some plants.
Genealogy
Genealogy refers to how a material is produced, and how it ages. Both can have interesting effects to the original materal, especially aging. For example, ethers do not age well because they can oxidize into peroxides. Peroxide compounds, or R-O-O-R compounds, can be volatile, and explosive if they are exposed to heat or shock. Initially, ethers are much more stable than peroxides. Many substances can readily oxidize to form peroxide substances, and some even form crystallized substances. Crystals should be treated as a warning sign, and the material should not be opened because of the risk of explosion.
Each of these products pertains to a specific hazard written about in this blog. Each SDS sheet for these products contains pictograms from the GHS label ID Card that I stuck to my forehead.
