Glass is a wonderful material with unique properties and an incredible range of uses in architecture, science, technology, and the arts. However, it can also be dangerous or even deadly – primarily because it is very sharp when broken.
Glass is dangerous because of its extreme sharpness. Broken glass injuries include cuts, deep-level lacerations, shock, severed limbs, & even bleeding to death.
Learn all about broken glass injuries – and how to avoid them in this comprehensive post.
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Why is glass dangerous?
The primary property that makes glass dangerous and life-threatening is its sharpness. Secondary reasons include the weight of glass panels, their precarious situation in high buildings, and the occasional spontaneous failure of tempered glass. Finally, less important problems include burning caused by the reflectivity of glass.
- Broken glass is extremely sharp
- Glass panels are very heavy
- Tempered glass can spontaneously break
- Glass can reflect and concentrate heat
Jump to this section for lurid details – examples of notorious and shocking glass injuries
Broken glass is extremely sharp
The reason for the extraordinary dangerousness of glass is the sharpness of a freshly broken edge – arguably the sharpest edge in nature and literally sharper than a razor blade.
When annealed (ie non-tempered) glass breaks it forms shards – large or small triangular fragments that act like daggers with sharp points and edges. A large shard can cause amputations or fatal injuries due to exsanguination (bleeding to death).
Most injuries are caused by people accidentally walking into a glass door or window or falling through a tabletop and the most common cause, reported in hospital ER departments, is that the victim was inebriated.
Injuries caused by wired glass
In the early 2000s, experts estimated that there were at least 2,300 school injuries yearly from unsafe wired glass. This type of glass was previously categorized as “safety” glass for its ability to prevent the spread of fire, but instead presents a serious danger because the wire makes the glass easier to break – with very serious consequences:
Wired glass was made illegal in the USA after 2003. Read all about the dangers of wired glass in this post.
Learn how to avoid sharp glass shards through the process of tempering.
Read all about tempering glass tabletops in this comprehensive post.
Best-selling and affordable – this compact first-aid emergency kit contains 298 pieces. Available on Amazon. Note – OK for minor cuts but for severe lacerations stop the bleeding and rush the patient to the ER.
Glass panels are very heavy
Even though tempered glass breaks into small harmless (“popcorn”) fragments, these fragments can remain clumped together and cause blunt force injuries. The same problem can occur when large panels of glass (with or without their frames) detach and fall from tall buildings as in the amazing example shown below:
Notice that the glass panel was tempered (it exploded into thousands of pieces with no shards) but the survival of this Saudi gentleman was due to his serendipitous position on the sidewalk – fractionally away from a direct head impact.
Tempered glass can spontaneously break
Inclusions in tempered glass can result in the glass spontaneously exploding. The most important type of inclusion is composed of nickel sulfide (NiS) which is incorporated by accident into the glass melt by contamination with nickel from stainless steel.
When the NiS stone, frozen into the tempered glass, gradually expands and re-equilibrates, the increased volume can cause the glass to fail suddenly.
Manufacturers take great care to minimize the risk by controlling contamination and by scanning glass to identify stones – so the risk is extremely low these days. However, homeowners still occasionally report the spontaneous shattering of their tempered glass patio table.
Glass can reflect and concentrate heat
Unusually shaped buildings
A very unusual source of danger from glass comes from its reflectivity. This property used routinely in telescopes, caused unpredicted and unwanted focusing of the sun’s rays when the London skyscraper at 20 Fenchurch Street (nicknamed the “Walkie Talkie”) was unveiled in 2014.
For a couple of hours in the afternoon, if the sun shines directly on the building, street temperatures of 117 degrees C (243 degrees F) have been measured and shown to cause serious damage to parked vehicles.
Glass snow globes and mirrors
Glass collectibles such as paperweights, hand mirrors, and snow globes have been the cause of several fires in residences and shops in recent years.
These objects, placed on window ledges, have acted like lenses to concentrate the heat of the sun. Read about these examples from a Missouri thrift store and a home in Kent, England.
Sources of injuries caused by sharp glass
The extreme sharpness of glass produces surface-level cuts, deep-level lacerations, shock, severed limbs, and bleeding to death.
For example, if a glass shard is large enough to penetrate the body almost all the way through, a severed limb can result. If even one shard of glass strikes a vulnerable location, it can lead to a severed artery causing the victim to bleed to death if medical help does not arrive quickly.
The commonest types of glass injuries occur in:
- Automobile accidents
- Broken window glass in buildings
- Glass tabletop injuries
- Broken glass in glass factories
- Broken glass bottles & containers – street litter
Automobile accidents involving glass
Modern glass windshields are made from two layers of tempered glass held together by a polyvinyl (PVB) interlayer. The vinyl interlayer holds the broken glass in place in the event of a crash but problems arise during high-speed collisions where even the laminated safety glass windshield can be dangerous.
Furthermore, most side and rear windows are not made of laminated glass so injuries can result to passengers and even bystanders due to flying shards of broken glass.
Broken window glass in buildings
These days there are strict building codes that mandate the use of tempered (safety) glass in doors and windows that are in close proximity, and therefore danger, to the public.
However, older buildings may still have old-fashioned annealed glass and most accidents are caused by people accidentally walking or falling into the glass.
A common cause of cuts in schools and public buildings is broken wired glass. This type of glass, mistakenly believed to be safety glass, actually breaks more easily than regular glass and the sharp broken wires often cause serious injuries.
Glass tabletop injuries
Annealed glass can cause severe accidents if used incorrectly for an unsupported table top. In the example dramatized in the illustration below, a University of Arizona student almost died as a result of a shard of glass puncturing his lung:
An ashen-faced father recounted the saga of his student son’s activities on one fateful evening at the University of Arizona. This exuberant undergraduate got drunk in his dorm room and danced on top of his glass coffee table. The annealed glass broke and the student was impaled by a shard of glass that entered through his back and punctured his lung. The father, fresh from the emergency department, wisely ordered tempered glass!
Learn whether your tabletop should be tempered or annealed.
When in doubt – play it safe with a tempered glass tabletop. This 42″ round clear glass top is 1/2″ thick and features an Ogee edge – available for a great price on Amazon.
Broken glass in glass factories
Workers in glass factories have to be especially careful when handling large heavy sheets of annealed glass. The infographic below summarizes safety measures:
Best-selling, cut-resistant gloves protect hands from cuts and punctures while handling sharp metals, knives, and glass, Do not take chances with your life!
Broken glass bottles – “street glass”
Numerous injuries in the inner cities are caused by street glass – accidents due to kids playing without footwear, on sidewalks littered with broken bottles.
Parents: never let your children play in city streets without footwear!
Annealed and tempered glass
Accidents caused by glass shards can be totally avoided by using tempered glass instead of annealed. Tempered glass is a safety glass that busts into thousands of harmless fragments when it fails.
Follow this link to learn whether your glass tabletop should be tempered and study this post for more info on the tempering process. To learn whether your glass is tempered or annealed – follow this link.
The other main type of safety glass is called laminated and is made by sandwiching a layer of vinyl between two sheets of tempered or annealed glass.
When the glass breaks, the vinyl holds the glass fragments together – minimizing the chances of injury,
Tragic events related to broken glass
Warning – this section contains material that some readers may find disturbing
Kristallnacht & broken windows
No student of history can fail to link broken glass with the notorious Nazi pogrom of November 1938 when anti-Semitic mobs destroyed Jewish homes, shops, and synagogues throughout Germany. The name Kristallnacht came from the shards of broken glass, from Jewish-owned businesses, that littered the streets.
Later, the “broken windows” policing philosophy, first formulated in the 1980s, used broken glass as a symbol of urban decay and the consequent breakdown of law and order.
Aztec human sacrifices
Readers with a taste for the macabre might reflect that the Aztecs used razor-sharp natural glass tools (made from volcanic obsidian) to efficiently cut out the still-beating hearts of their sacrificial victims.
Bottles as offensive weapons
Horrific facial, scalp and other injuries are caused by criminals using broken bottles as offensive weapons. In slang, the activity is known as “glassing” and is commonly used by gang members and street thugs.
The glass guillotine
Karger et. al 2001, describe a fatality caused when a triangular portion of a broken glass window detached from the top of the window frame and decapitated the victim in the manner of a guillotine execution.
In the same interesting article, the authors summarize their findings in a Berlin autopsy study as follows:
“A typical pattern was present in 15 cases: inebriated adults fell into an architectural glass surface in the form of a door or window (12 cases), an aquarium, a mirrored wardrobe, or a telephone cell. Another man fell into a large drinking glass. Many victims in this group showed multiple scratches, abrasions, and superficial incisions as well as one or more deep tear/cut/puncture injuries”.
Student dies from glass wounds in Bethany WV
In a case reported by Glass Magazine (1986), a seventeen-year-old freshman at Bethany College in West Virginia was accidentally killed when he ran through a plate glass window while hurrying to get to a meeting in one of the campus buildings.
“Brian Spruill, who was late for an afternoon football meeting, mistook one of the floor-to-ceiling sidelites located on either side of a glass double entryway, for the door and he crashed through the glass. Spruill was rushed to the hospital but died, after surgery, from a shard of glass that had punctured his heart.”
According to the college facilities superintendent, the building where the accident took place was constructed in 1964, before safety glazing requirements were developed.
The barman’s creed
It is a well-known code of practice in the bartending business never to scoop up ice with a glass – always use a metal or plastic ice scoop.
This best-selling polycarbonate ice scoop, made from clear plastic, is available on Amazon. 12-ounce capacity – used for safe handling of ice.
If broken glass gets into the ice compartment the whole unit has to be drained out and cleaned, The consequences for glass chips in cocktails can be injuries to patrons and potential lawsuits.
The victim causes the cuts
It is interesting to note that, unlike cases of stabbing (or impaling by Vlad), it is the motion of the victim (falling into a broken glass window) that causes the wound – not the motion of the glass or the dagger.
The weight and momentum of the stumbling (sometimes drunk) victim, falling onto the glass shards is what causes the lacerations. Injuries are often exacerbated by the victim, in a state of shock, trying to rapidly withdraw his hand from a broken window causing still further cuts.
Collapsing swimming pool
A luxury swimming pool at the Sandals resort in Curacao collapsed when the “infinity” glass wall gave way recently. The failure of the laminated and tempered glass was blamed on an excessive number of swimmers enjoying the pool.
Luckily there were no fatalities but numerous bathers were injured as tons of water washed them and broken glass hundreds of yards down the beach.
Extracts from the press report stated: “Curaçao police say their initial investigation suggests the glass broke because too many people were in the pool during a party, according to local media.”
Bar and nightclub director Mr. Jones, 44, added: “We’d only been in the resort less than 24 hours and were having a few drinks. I was standing with my back to the sea chatting to my wife when one of the panels in the middle of the pool just disappeared. The weight of the water took me, Elizabeth, and a lot of other people and washed us about 30 yards down the beach”.
Glass tabletops & shelves – info from Artistry in Glass
- Benefits of glass shelving – info from experts!
- How much do glass tabletops cost?
- Do glass shelves need to be tempered?
- What is the best thickness for glass shelves?
- Best edge type for glass shelves, polished or beveled?
- How much weight can a wall shelf carry?
- What color glass should my shelves be?
- Glass tabletops – 10 amazing benefits explained
- How to order a glass tabletop
- Best thickness for glass tabletops – expert advice
- Should glass tabletops be tempered?
- Should glass tabletops be beveled?
- How to paint a glass tabletop
- All about tempering glass tabletops!
- How to tell if your glass is tempered
- Can tempered glass be cut?
- How to protect your wood table with glass
- How to fix a scratched glass tabletop
- How to fix a chipped glass tabletop
- How to replace broken patio table glass
- How to measure for a glass tabletop
- Video – how to measure your tabletop
- Plexiglass vs glass – pros and cons
- Beveled glass table base – a case study
- Choosing between tempered & laminated glass
- Glossary of terms used in the glass business
Glass safety – learn from the experts!
- Choosing between tempered & laminated glass
- Broken glass injuries and how to avoid them
- Is wired glass safe?
- What is safety glass?
- What is tempered glass?
- What is Gorilla Glass?
- Plexiglass vs glass
- Should glass shelves be tempered?
- Should glass tabletops be tempered?
- Is lead crystal dangerous?
- Is leaded (stained) glass dangerous?
- How to repair cracked stained glass