Odd but interesting question about slabs - I didn't have an answer!

[James_OldeTowne]

I did the St. Louis one-day show (small) this past weekend. People who come to this show mostly collect raw coins. One older fellow walked up with an odd question about slabs, though. Basically, he wanted to know if slabs represent a fire hazard. We also got into the question of whether they would put out toxic fumes if they melt or catch on fire.

 

Anyone have a clue how to answer this question?

 

Thanks.

 

James

[XpipedreamR]

There are lots of them. Any carbon-based material produces hazardous

products under most combustion conditions, mostly due to incomplete

combustion. For instance, burning gasoline can produce carbon monoxide

and hydrocarbons, burning charcoal can produce carbon monoxide, and

burning methanol can produce formaldehyde.

Some types of plastic contain elements besides the standard carbon,

hydrogen, and oxygen. Nylons contain nitrogen, and polyvinyl chloride

contains, of course, chlorine. These constituents also find their way into

the combustion products. Probably the particular component you have heard

about most is TCDD, which is an abbreviation for the chemical name

tetrachloro-dibenzo-dioxin. This compound contains four chlorine atoms, and

is inevatibly formed when polyvinyl chloride plastics are burned. (Complete

combustion of PVC would yield only water, carbon dioxide, and hydrogen

chloride; in practice, some incomplete combustion products such as TCDD are

always formed, if at low levels.) TCDD is also formed when wood burns,

because wood also contains small amounts of chlorine. Because of the much

higher proportion of chlorine in PVC, however, it is the material leading to

the highest levels of TCDD.

The toxicity of TCDD to animals is well-established. It is often considered

to be the man-made compound most toxic to animals. Its toxicity to humans,

however, is not as well-established. The only absolutely confirmed human

health effect from exposure to TCDD is a skin rash called chloracne. Other

health effects are suspected. It is considered a carcinogen on the basis of

animal studies.

TCDD is also an unwanted by-product of the manufacture of the herbicides

2,4-D and 2,4,5-T. A manufacturing accident at a plant manufacturing these

chemicals occurred near Sevesto, Italy in 1976 released an estimated 1-10 lb

of TCDD into the surrounding countryside, killing many farm animals and

causing chloracne. Since 2,4-D and 2,4,5-T were components of the defoliant

"Agent Orange" used in Vietnam, many U.S. servicemen (and of course

Vietnamese) were exposed to elevated levels of TCDD. TCDD is thus suspected

as the cause of the symptoms attributed to "Agent Orange" exposure.

 

Richard E. Barrans Jr., Ph.D.

Assistant Director

PG Research Foundation, Darien, Illinois

 

 

 

 

 

 

 

 

 

PS: I am not Richard Barrans!

 

 

[TomB]

That's an interesting question I had never thought of before. Off-hand, I would think that slabs would be no more of a fire hazard than any other plastics found in the home including, but not limited to, building materials, kitchen appliances, telephones, TVs, computers, printers, toiletries, furniture, toys and food grade plastics such as bags. As for toxic fumes, again off-hand I would equate them with the previously mentioned products.

 

The quote from XpipedreamR is also interesting, but I think much of it is not relevant. I write this because the entire section on TCDD (almost the entire response) is likely a moot point since I believe that slabs do not contain PVC and are therefore unlikely to be able to produce TCDD.

[Leothelion]

I did the St. Louis one-day show (small) this past weekend. People who come to this show mostly collect raw coins. One older fellow walked up with an odd question about slabs, though. Basically, he wanted to know if slabs represent a fire hazard. We also got into the question of whether they would put out toxic fumes if they melt or catch on fire.

 

Anyone have a clue how to answer this question?

 

Thanks.

 

James

 

They will if it's a pcgs slab!

 

Leo