Design Life-Cycle

Camille Vistica

Professor Christina Cogdell

Design 40A

13 March 2014

The Embodied Energy of Stone Countertops

Stone countertops are in most homes nowadays and used everyday without thought. However, no one realizes the amount of energy necessary to get the stone out of the ground and into their house. This amount is called the embodied energy and includes all energy used in producing a product. The production process of countertops varies from stone to stone but remains altogether similar, while the embodied energies greatly differ. There are three steps all types of stone have in common when it comes to making them into countertops; the stone is extracted at a quarry, then moved to a processing plant where it is made into usable forms before it is shipped to its final destination. The calculation of embodied energy begins at the quarry.

The Elsevier journal published a study on the embodied energy and embodied CO2 in UK Dimension Stone, which is defined as granite, sandstone, slate and limestone, and labeled the LCA, or Lifecycle Assessment, as “generally poor”. The surface numbers for embodied energy are: .122 Mj/kg of sandstone, .208 Mj/kg of slate, 5.908 Mj/kg of granite, and .964 Mj/kg of limestone. Sandstone was studied on a cradle-to-gate analysis while the other three were studied on a cradle-to-site analysis. Different studies have different definitions of cradle-to-gate and cradle-to-site but in the simplest terms this study defines cradle-to-gate as the energy from the quarry, processing plant and any transportation in between and cradle-to-site as the energy from the quarry, the processing plant, the transport in between and transport to the final destination in the UK; this considers direct fuel usage only. Going into greater detail, the quarry includes energy from heavy machinery, on-site transportation (lorries and loaders), backfilling, waste and scrap disposal, and use of black powder. The processing plant needs energy for on-site primary and secondary drills, on-site facilities such as heaters, dust extractors and offices, disposal of waste and scrap, and on-site transport like a forklift. Up to this point is classified as cradle-to-gate; cradle-to-site further includes the energy of distribution which is only the energy used to transport material to the site. The parameters of this LCA, do not include the manufacture and maintenance of machinery and vehicles, the water use on-site, the construction and maintenance of buildings or the production of black powder and explosives.

The process begins at stone quarries around the world in countries such as Portugal, Spain, Italy, Poland, Brazil, India and China. According to the Dimension Stone article, these are the countries from which the UK gets their sandstone, granite and slate. The measurement of embodied energy begins when the explosives and black powder are used to unearth the desired stone. A different source reveals that granite is buried under layers of sedimentary rock, so it is safe to assume that most types of stone are also buried under the earth and therefore require explosives to expose them. The goal is to extract as much raw material as possible while damaging as little as possible. The level of difficulty varies between types of stone. For example, this is a difficult task when it comes to slate and 85% becomes unusable. The percentage is less for granite, at 47%, and even less for sandstone, which creates 29% of scrap. So this unusable material does not go to waste, most quarries put scrap stone toward something else, like lower-grade byproducts, landscaping material, and plastic products and aggregate where fine dust is used as filler. This action reduces waste so that practically nothing goes into the landfill. However, even with this fact, the embodied carbon is still a high number due to other steps of the lifecycle.

After extraction, the raw material then goes to the processing plant where the stone is cut to the necessary size and shined. This is the most extensive component in the cradle-to-gate version, because within this one step, there are numerous stages and each stage requires a variety of machines. Such machines include a primary diamond wire cutter, a secondary diamond wire cutter, a chainsaw, hydraulic jacks, splitting wedges, cushions, stationary wire saws and a few others as well. Electricity powers the machines, the dust extraction devices, water pumps, and office and retail buildings, while diesel and petrol power the drills, excavators, front loaders, dumping trucks, explosives and finished stone transportation. Lastly, oil is used for finishing, shrinking and wrapping of the product.

 The UK Dimension stone article suggests that in order to reduce emissions and amount of energy used, researchers could use renewable sources of energy, transport the stone in hybrid vehicles, use local water for hydroelectricity and encourage people to buy local stone. An example of a company that is trying to attain this goal is a Spanish quarry that uses photovoltaic electricity, which supposedly has no impact on the landscape. With no information provided about this quarry, it comes across as a questionable example, if it were successful why aren’t more companies using photovoltaic energy? At this step in the process, the cradle-to-gate process is done and the embodied carbon for sandstone, granite and slate is 64 kgCO2e/tonne, 92.9 kgCO2e/tonne, and 232 kgCO2e/tonne, respectively. The reason that slate’s embodied carbon is significantly higher than the others is because all slate quarries are concentrated in one area and the processing plants are all over the UK, as opposed to the other stones where operations are normally regional or local. The carbon dioxide emissions easily show the impact transportation has on the environment, even if it is the short distance from the quarry to the production plant in the UK.

Some companies go out of their way when bringing the stone from the quarry to the production plant. One would think it obvious to take the shortest routes but this is not the case. Conversely, corporations transport stone all the way across the globe in search of cheap labor for processing. Frequently, excavated stone is sent to China or India to be processed because the workers are paid so little. After the stone has been cut, shined and finished, it is sent back to the United States or European Union. Not only is this whole ordeal inefficient, it is a waste of energy and hurtful to the environment.

The numbers show just how hurtful one trip to China can be, emissions and energy use increase by 550%. The embodied carbon of sandstone that does not leave the UK is 77.3 kgCO2e/tonne, 312.3 kgCO2e/tonne if it goes to India and 504 kgCO2e/tonne if it is processed in China. Similarly, for granite the numbers rise from 158 kgCO2e/tonne, to 161.2 kgCO2e/tonne for Spain and 415.5 kgCO2e/tonne for China. And finally, slate in the UK requires 297.4 kgCO2e/tonne, 318.2 kgCO2e/tonne in Spain and 568.1 kgCO2e/tonne in China. Obviously, the way to circumvent these numbers would be to stop using cheap labour from other countries, or if the stone that one comes directly from overseas, try to buy stone from local companies so the polluting trip becomes obsolete. Unfortunately, since most people will continue to buy the cheapest option. A good way to lessen the amount of energy used in somewhere like China is to configure the infrastructure so extraction sites are in close proximity to processing plants. Currently there are 27 quarries in the North, East and West regions of the country while there are two processing plants in the South.

The whole system is inefficient but unfortunately the need for cheap labor is an integral part of the capitalist system and will therefore remain a factor in the production of most goods including stone countertops. An alternative to this global trade is to keep the quarrying, processing and sale local, however, according to a study conducted by the University of Athens that explores marble quarries finds they are not entirely efficient either.

This study, by the University of Athens, focused on the embodied energy of Greek marble. Researchers found that the majority of processing plants are owned by Small-to-Medium Enterprises dubbed SMEs and because of this, have limited funding and do not have to adhere to as many government rules. An energy audit shows that the gangsaw uses 123 kilowatts, the polishing machine 116 kilowatts, waste water treatment 15 kilowatts, and 625 kilowatts a day from the electricity grid. The quarry runs 12 months a year and eight hours a day. An average American household in 2012 used only 29.13 kilowatts a day, clearly marble quarries are not very efficient. Furthermore 75 kilowatts of energy is consumed for each block that is excavated, 140 kilowatts for transport, and 693.7 kilowatts for cutting. The excavation process is 90% effective and the average efficiency of all the steps included in cutting the block is 94%.

Unfortunately, decreasing embodied energy is a difficult process because new machinery and technology are needed for significant improvement. Studies show that a 50% increase of belt speeds creates 20% less energy consumption, and stacking the marble 10 centimeters closer also reduces energy consumption. There are few changes like this that can be made, for example decreasing the amount of UVA lights by 25% only decreases energy consumption by 1%. There have to be more effective ways to use less energy. In lieu of this, the European Union created the eco-label, which promotes efficiency and sustainability improvements to be taken by the brand and the customer, who is encouraged to buy brands that have the eco-label. The criteria for the label is to have a water recycled to water leaving ration of 65%, usable material output of 65%, a noise level of 60 decibels, good air and water quality, and low percentage of affected area. Any energy consumption improvements reduce greenhouse gas emissions and improve the sustainability of the plant. The embodied energy of a slab of Italian marble is 324.4 kW/m3 while a slab of Greek marble uses only 100-160 kW/m3. This discrepancy is due to the fact that Greek marble is of higher quality and requires less strengthening and has fewer cracks to fill.  

This study focused on the embodied energy of Greek marble. Researchers found that the majority of processing plants are owned by Small-to-Medium Enterprises dubbed SMEs and because of this have limited funding and do not have to adhere to as many government rules. An energy audit shows that the gangsaw uses 123 kilowatts, the polishing machine 116 kilowatts, waste water treatment 15 kilowatts, and 625 kilowatts a day from the electricity grid. The quarry runs 12 months a year and eight hours a day. An average American household in 2012 used only 29.13 kilowatts a day, clearly marble quarries are not very efficient. Furthermore 75 kilowatts of energy is consumed for each block that is excavated, 140 kilowatts for transport, and 693.7 kilowatts for cutting. The excavation process is 90% effective and the average efficiency of all the steps included in cutting the block is 94%.

In our research, we found it difficult to learn about two topics; the recycling of the product and how the stone is specifically made into countertops at the processing plant. Since there is no information on recycling of countertops, I am assuming that when a house is torn down the stone is just thrown in a landfill or repurposed and used as something else. There was also no real information on countertops themselves, the article about Greek marble however, was about the production of tiles. I think it is safe to assume that the process for countertops is similar to that of tiles, and if not the processes are the same until the stone is cut into tile-sized pieces, which occurs at the end of the process anyways.

In conclusion, the majority of the embodied energy of a stone countertop comes from the transportation of stone from facility to facility. The best way to combat this would be to stay local in your production and sale of the finished product. Another way to lower the embodied energy would be to find renewable sources to power the machinery at the quarry and the plant. Sadly, it is difficult to change either of these problems because the capitalistic consumer society inhibits us from seeing the bigger picture that is beyond the scope of our world. In order to change this phenomenon, the public needs to be educated about where their belongings are coming from and what kind of process is needed as well as how much energy it takes to make their kitchen counter beautiful.

Bibliography

Crishna, N., P.f.g. Banfill, and S. Goodsir. "Embodied Energy and CO2 in UK Dimension Stone." Resources, Conservation and Recycling 55.12 (2011): 1265-273. Print.

Gazi, A., G. Skevis, and M.a. Founti. "Energy Efficiency and Environmental Assessment of a Typical Marble Quarry and Processing Plant." Journal of Cleaner Production 32 (2012): 10-21. Print.

"Granite - How Its Made." YouTube. YouTube, 26 Jan. 2010. Web. 13 Mar. 2014.

Gunn, J., and D. Bailey. "Limestone Quarrying and Quarry Reclamation in Britain." Environmental Geology 21.3 (1993): 167-72. Print.

Material Life Embodied Energy of Building Materials. N.p.: Cannon Design, 2013. PDF.

"U.S. Energy Information Administration-EIA." How Much Electricity Does an American Home Use? N.p., n.d. Web. 12 Mar. 2014.

Christian Quintana

Professor Christina Cogdell

Design 40A

13 March 2014

Stone Countertops Waste & Emissions

Imagine building a home or buying one. Upon touring the new home the kitchen is the prized room of the house with realtors enthusiastically describing the new appliances and countertops the kitchen has. It is also the go to room for a remodeling project in an outdated home. Choosing out the appliances and paint color are obviously essential for a kitchen but a huge factor of the kitchen design falls to the countertop. Soapstone, quartz, slate, and the most sought after stone of them all-granite, are just a few different types of countertops available. Stone countertops are essentially as straightforward as they seem but still require work that is not known as common knowledge to house lovers. Cutting away at a lemon, thoughts are centered on not cutting a finger rather than the lifecycle of a countertop. Everyday countertops are used without really acknowledging how they came about, who had to suffer, and what kind of waste was created to acquire a beautiful piece of interior architecture. Interior designers need to become more aware of the waste and emissions caused by the production of stone countertops because if I cannot find enough information on stone countertops how can they consciously decide what stone to choose. The natural stone needed to develop the countertop of your desire requires extraction of that specific stone from the earth. Mining, explosives, drilling, diamond wire cutting are some ways that are used to take the stone out of the ground. Drilling and diamond wire cutting are the main methods of quarrying with 80% done by drilling and 20% done by diamond wire cutting.[1] I could not find information how much pollution was emitted from drilling, relating to stone or not. In fact, it was fairly difficult to find information on what type of waste or emission occurred when using this technique. I researched searched the same thing but for techniques that did not necessarily refer drilling. Explosives are another method of extracting a chunk of stone out of the ground and so I decided to search for information on the toxins of explosives. “Carbon monoxide is the pollutant produced in greatest quantity from” using almost any type of explosive.[2] I assumed that this would be the case for any type of explosive used for extraction of the stone. Assuming large amounts of it would not be released, carbon monoxide released through repeated stone extraction by the use of explosives could seriously harm humans if persistence and a high demand of stone countertops continue.[3] Carbon monoxide being released into the air is clearly not a beneficial chemical release into the air. Interior designers should realize the significance of acquiring stone countertops because it is detrimental to human health even without direct association. The blasting method to excavate stone is not the only harmful method of stone extraction. Diamond cutting can also produce toxicity. Water is used to clean the slab of stone, in this case marble or stone, collecting dust from the cut but that water becomes toxic with levels of alkaline.[4] The water is extremely dangerous and if disposed of improperly or into a water supply it can seriously harm humans and animals. In Egypt, where this takes place, water containing the granite slurry is dumped onto the ground where it evaporates emitting harmful particles into the air.[5] Proper disposal of the slurry is not taken. This type of waste should be disposed of properly and although this article refers to events in Egypt I assumed similar action could be taken in the United States. Non-radioactive by-products are generally not produced, therefore preventing climate change, but plant life is destroyed by most extraction methods.[6] The death of plant life is not so concerning to many humans today and do not realize the harm in destroying it which causes resources to be used in planting more and more until it develops into a cycle. The items used in the actual method of extraction, like “worn steel grit and blades” can also cause toxic waste like transferring Chromium into “surface and ground waters”.[7] This affects the water of workers and families, endangering their lives for the sole purpose of providing homes with a granite countertop. I assume that this type of disposal method occurs elsewhere, maybe not the United States but in other countries, causing a global waste. This method affects the lives of workers and families near the stone extraction site; because it may not affect Americans directly they are unaware of the harmful effects of attaining stone to create their countertops.

Stone countertops, for the most part are not locally found. I could not find any information on how many stone quarries there are in the United States but it can be assumed that wherever stone is extracted for the countertop it must be transported to another location for it to be cut or polished. In this instance I searched for information on waste caused by trucks that are used to transport commercial items. The number of gallons of diesel or petroleum used by commercial trucks has steadily increased through the years.[8] The consumption of diesel or petroleum should be steadily decreasing rather than increasing and the need to transport stone countertops is not a helping factor. The transportation of these large stone slabs poses a threat to the environment because of the fumes emitted by the trucks. “70 percent of the cancer risk from the air we breathe is attributable to diesel PM” which is particulate matter caused by diesel commercial trucks.[9] That stone slab being transported to a company near you is also transporting unwanted health risks. Not only should interior designers understand these effects of stone transportation they should realize how they contribute to the already large portion of transportation pollution. Besides the cancer risk that becomes airborne through the use of truck transportation, the air becomes polluted as well. “Nitrogen oxide (NOx) emissions from diesel engines contribute to smog formation” which in turn affects the air needed to support life.[10] The stone necessary to attain the countertop of a client’s dream causes smog and health risks for it to be transported solely through the country. If acquiring the stone from another country it must be transported through cargo ships, which would cause more smog. Assuming that stone transportation uses cargo ships, they “produce carbon dioxide emissions that significantly contribute to global climate change and ocean acidification.”[11] Following a sustainable path towards obtaining stone will help mitigate environmental damage but not completely because of the steadily increase of fuel and diesel consumption. The actual creation of the product is not as harmful as obtaining the stone but it is still not safe.

Countertops do not retain their strength and sheen from the sole action of mounting the cut piece of stone onto the cabinets or wooden area of the kitchen. In order for countertops to be used the way they are they must be sealed. This means that it “will be protected against everyday dirt and spills.”[12] Kitchen countertops require chemicals to prevent these occurrences from happening. Without it those precious countertops desired by most homeowners would not be prevalent among kitchens. I assume most countertops are safe inside a home. Although radon is emitted from stone countertops, it is not enough to cause significant danger because radon concentration “was estimated to be at or below the EPA recommended-action level.”[13] Thankfully, this is one worry that homeowners and interior designers do not need to experience. However, they look past the danger in handling chemicals needed to seal the stone. Soterra Granite Sealer lists the possible hazard of using their product. Blindness or death may occur but only due to inhalation or ingestion in high concentrations.[14] Although it says high amounts, it is still an emission caused by a product needed to achieve the finished countertop. I assume that most sealers have a similar effect as this one. Sealers cannot protect granite from bacteria and I assume this applies to any porous stone used in countertops. Over 54 billion bacteria can grow in a granite countertop, even if sealed, and salmonella harbors in it greatly because it has somewhere to live, there is moisture, and food is provided.[15] Clearly, this beautiful stone so strongly desired by designers and homeowners alike, causes a threat to human health. Granite, or any stone that emits chemicals or fosters a home for bacteria should be a fact known to designers so they can limit the use of these stones.

Recycling is becoming an important part of human life since the fact that fossil fuels and other materials are being used in copious amounts. I could not find any information on recycling stone countertops. I should be able to find articles on recycling countertops because it should be occurring more often than not. The only aspect of recycling that is associated with stone countertops is a company that takes “scrap material” from granite countertop fabrication to create pavers or tile.[16] This particularly applies to a place in Atlanta and it can be assumed that places throughout the country do it too but not enough since there is little information regarding recycling and stone countertops. While it is something, it does not cover enough of the waste caused by countertops. I assume this indicates that there is not much recycling possible with granite countertops. This is provides more reason for designers and homeowners need to be more conscious of stone countertops and their waste. There is no waste or emission directly correlated with recycling stone countertops because for the most part they are not. For the most part granite countertops end up in the landfill. If not used in creating tiles like in Atlanta, then piles of garbage and waste become the new home for the countertops. Waste of these countertops contributes to the pollution caused by landfills. I could not find specific information on what happens to countertops but the recycling company mentions that granite waste will end up in local landfills.[17] Landfills are already too wasteful; the addition of countertops is unnecessary. Landfills also release gasses, which consist of “approximately 50% methane, 42% carbon dioxide, 7% nitrogen and 1% oxygen compounds.”[18] Essentially, the majority of the gas released is dangerous to the environment. The amount of methane released is alarming. While it is dangerous, it is a new source of renewable energy that can be used as an alternative to non-renewable ones.[19] There is a useful side to the putrid landfill. Rather than the pile of garbage sit there, it can have a use. However, the methane produced does enhance the production of green house gasses, which contributes to global climate change.[20] Countertops end up in landfills and landfills contribute to the advancement of global warming so therefore countertops help the advancement of global warming. Again, no information on the emissions or waste caused by direct waste management of stone countertops is available, like most of the other aspects of the life cycle of stone countertops.

There is no direct articles or information dealing with the waste and emissions of stone countertops. Digging deep into each of the aspects of the lifecycle of stone countertops, with some vacant information, it is astounding the amount of contribution stone countertops add to waste even if I assumed information. Their beautiful and earthy image masks the dirt, pollution, bacteria, smog and countless of other wastes and emissions caused by the details of producing stone countertops. Those countertops you find so charming emit harmful chemicals and gases, aid in the continuous production of smog, and can cause a worker to go blind. Interior designers, as well as homeowners, need to become aware of these problems. If information on these issues is not readily available to the public, then it is in the hands of these professional decorators to make environmentally conscious decisions.

Bibliography

"100% RECYCLED SOLID GRANITE LANDSCAPE PAVERS & TILE." Granite Recycling Process » GREENSTONE Products Online. N.p., n.d. Web. 08 Mar. 2014.

"Assessing the Effects of Freight Movement on Air Quality at the National and Regional Level." National Freight Transportation Trends and Emissions. N.p., n.d. Web. 04 Mar. 2014.

"Bacteria in Your Granite Countertop." Bacteria in Your Granite Countertop. N.p., n.d. Web. 06 Mar. 2014.

"California: Diesel Trucks, Air Pollution and Public Health." Union of Concerned Scientists. N.p., n.d. Web. 04 Mar. 2014.

"Carbon Monoxide (CO)." Department of the Environment. N.p., n.d. Web. 07 Mar. 2014.

"Chemicals Used in Granite Fabrication and Repair." Chemicals Used in Granite Fabrication and Repair. N.p., n.d. Web. 06 Mar. 2014.

"Energy Efficiency Opportunities in the Stone and Asphalt Industry." Energy & Resources Solutions, Inc., n.d. Web. 07 Mar. 2014.

"Getting Granite From International Quarries To SLABCO Granite Quarry Videos from St. Cecilia Quarry in Brazil." Granite Quarry to Slabco Marble and Granite, Inc. N.p., n.d. Web. 04 Mar. 2014.

Hamza, Rania A., Salah El-Haggar, and Safwan Khedr. "Marble and Granite Waste: Characterization and Utilization in Concrete Bricks." International Journal of Bioscience, Biochemistry and Bioinformatics (2011): 286-91. Print.

Kitto, Michael E., Douglas K. Haines, and Hernando DiazArauzo. "Emission of Radon From a Decorative Stone." N.p., n.d. Web. 07 Mar. 2014.

"Landfill Gas to Energy." Energy Systems Group. N.p., n.d. Web. 04 Mar. 2014.

"Marble Institute of America: Design Professionals - Sealing Natural Stone." Marble Institute of America: Design Professionals - Sealing Natural Stone. N.p., n.d. Web. 04 Mar. 2014.

"Marble Product Manufacturing Process from Hyperbetter Stone." Marble Product Manufacturing Process. N.p., 15 Sept. 2011. Web. 04 Mar. 2014.

Maryla. "How to Transport Granite Counters." Millennial Living. N.p., 12 May 2009. Web. 06 Mar. 2014.

Oliver, Rachel. "All About: Landfills." CNN. Cable News Network, 15 Oct. 2007. Web. 07 Mar. 2014.

"Pacific Environment : Shipping." Pacific Environment : Shipping. N.p., n.d. Web. 06 Mar. 2014.

Phillips, Margaret L., and Andrew C. Johnson. "Prevalence of Dry Methods in Granite Countertop Fabrication in Oklahoma." Journal of Occupational and Environmental Hygiene 9.7 (2012): 437-42. Print.

"Quarry Equipment - General Considerations." Graniteland. N.p., n.d. Web. 06 Mar. 2014.

Rodrigues, M.l.m., and R.m.f. Lima. "Cleaner Production of Soapstone in the Ouro Preto Region of Brazil: A Case Study." Journal of Cleaner Production 32 (2012): 149-56. Print.

Uglow, David. "Mitigating the Environmental Impact of Artisanal Quarrying: Consideration of Awareness and Incentives." N.p., n.d. Web.

United States. Environmental Protection Agency. Explosives Detonation. Fifth ed. Vol. 1. N.p.: n.p., n.d. Web. 07 Mar. 2014.

"Vital Graphics." Climate Change and Waste. N.p., n.d. Web. 09 Mar. 2014.

"World-petroleum.org." World Petroleum Council. N.p., n.d. Web. 06 Mar. 2014.

{C}[1]{C} "Quarry Equipment - General Considerations." Graniteland. N.p., n.d. Web. 06   Mar. 2014.

{C}[2]{C} United States. Environmental Protection Agency. Explosives Detonation. Fifth ed. Vol. 1. N.p.: n.p., n.d. Web. 07 Mar. 2014.

{C}[3]{C} "Carbon Monoxide (CO)." Department of the Environment. N.p., n.d. Web. 07 Mar. 2014.

{C}[4]{C}   Hamza, Rania A., Salah El-Haggar, and Safwan Khedr. "Marble and Granite Waste: Characterization and Utilization in Concrete Bricks." International Journal of Bioscience, Biochemistry and Bioinformatics (2011): 286. Print.

{C}[5]{C} Ibid.

{C}[6]{C}   Hamza, Rania A., Salah El-Haggar, and Safwan Khedr. "Marble and Granite Waste: Characterization and Utilization in Concrete Bricks." International Journal of Bioscience, Biochemistry and Bioinformatics (2011): 287. Print.

{C}[7]{C} Ibid.

{C}[8]{C} "Assessing the Effects of Freight Movement on Air Quality at the National and Regional Level." National Freight Transportation Trends and Emissions. N.p., n.d. Web. 04 Mar. 2014.

{C}[9]{C}  "California: Diesel Trucks, Air Pollution and Public Health." Union of Concerned Scientists. N.p., n.d. Web. 04 Mar. 2014.

{C}[10]{C} Ibid.

{C}[11]{C} "Pacific Environment : Shipping." Pacific Environment : Shipping. N.p., n.d. Web. 06 Mar. 2014.

{C}[12]{C} "Marble Institute of America: Design Professionals - Sealing Natural Stone." Marble Institute of America: Design Professionals - Sealing Natural Stone. N.p., n.d. Web. 04 Mar. 2014.

{C}[13]{C} Kitto, Michael E., Douglas K. Haines, and Hernando DiazArauzo. "Emission of Radon From a Decorative Stone." N.p., n.d. Web. 07 Mar. 2014.

{C}[14]{C} "Chemicals Used in Granite Fabrication and Repair." Chemicals Used in Granite Fabrication and Repair. N.p., n.d. Web. 06 Mar. 2014.

{C}[15]{C}  "Bacteria in Your Granite Countertop." Bacteria in Your Granite Countertop. N.p., n.d. Web. 06 Mar. 2014.

{C}[16]{C} "100% RECYCLED SOLID GRANITE LANDSCAPE PAVERS & TILE."Granite Recycling Process » GREENSTONE Products Online. N.p., n.d. Web. 08 Mar. 2014.

{C}[17]{C} "100% RECYCLED SOLID GRANITE LANDSCAPE PAVERS & TILE."Granite Recycling Process » GREENSTONE Products Online. N.p., n.d. Web. 08 Mar. 2014.

{C}[18]{C} "Landfill Gas to Energy." Energy Systems Group. N.p., n.d. Web. 04 Mar. 2014.

{C}[19]{C} Ibid.

{C}[20]{C} "Vital Graphics." Climate Change and Waste. N.p., n.d. Web. 09 Mar. 2014.