Cobalt Sundrops are made from Skyy Vodka bottles One of the most common questions we get is, “Is the glass recycled?” Although it turns out that the glass has a smaller environmental impact than other materials in a pair of earrings, I certainly understand how recycled glass provides a more intuitive feeling of environmental consciousness than being able to say that they came on a smaller, recycled paper card, for example.

Invariably the next question is “Which colors are recycled, and what glass do you use?”

• We use Bombay Sapphire Gin bottles to make our ‘Water’ color Sundrops
• Skyy Vodka bottles turn into ‘Cobalt’ Sundrops
• Various screw-top beer bottles are used for ‘Bottle Brown’ (Shaun and I have the re-cappable bottles for brewing our own beer)
• We use Jagermeister bottles to make our ‘Kelly Green’ Sundrops
• We have used various wine bottles in the past, but find that the colors are highly variable, ranging from Kelly Green through many shades of olive to brown. We’ve generally found the pure Kelly Green and Bottle Brown to be more popular than any of the in between olive shades.


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Example of a Prop 65 warning label Recently, a California store expressed interest in carrying Sundrops if we could say our jewelry complies with the state’s Proposition 65 (the Safe Drinking Water and Toxic Enforcement Act of 1986). Prop 65 lists twenty-one pages of chemicals known to cause cancer, and is the reason for the tags you sometimes see on appliance cords and many other things.
The Good News
Lead was the easy one; most items are labeled if they contain lead. Figuring out whether any of the other myriad of proscribed chemicals were present was much more difficult. I spent a few solid days searching the internet, sending emails to the makers of materials we use, and chatting online with the primary middleman from whom we purchase most of our jewelry findings (ear hooks, wire, necklace cord, etc) to get either the list of materials in each item or the maker’s declaration that the item complies with Prop 65. However, I can now happily say that all of our jewelry findings are in compliance with Prop. 65. This does not necessarily mean that they contain no chemicals listed in those 21 pages, it just means that any of those chemicals are present in low enough concentrations to not require a warning label.

That list, by the way? It was rather less helpful than it could be - it doesn’t list what the allowable levels are for each chemical, which was irritating to me from two perspectives:

• as a business owner, it was very difficult to determine whether my product is allowable
• as a person wanting to be protected from these chemicals, I don’t know what levels are considered safe

The Bad News
While our jewelry findings are clean, not all of our glass is. Two of the roughly 20 colors of stained glass we have used contain lead. Lead in glass jewelry is not actually a health hazard to those wearing the jewelry (lead in glass can’t leach the way metallic lead can), although it still has to carry the warning label. The potential health hazard is for us, the people melting the glass. Although the lead is trapped inside the glass when solid, melting releases toxic lead fumes. Even though our glass melting takes place in a well-ventilated space (i.e. outside - concentrated sunlight, remember? ) we’d rather not expose ourselves to that. We are discontinuing making these two colors immediately, and will not be shipping them to any stores carrying our jewelry. The remainder of these colors will be sold through our webstore with the appropriate legal warning.

So, our jewelry (except those two discontinued colors) is in compliance with Prop 65, and I’ll be trying out some new lead-free glass colors as soon as the weather improves.

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Last week I talked about the impact of the glass industry in general. Today I’m going to get a little more specific.

Bullseye Glass
Some of our glass comes from recycled bottles, but most of it comes from the Bullseye Glass Company in Portland, Oregon.


Bullseye Glass being made - from their website I emailed Bullseye about their energy usage and was pleased to find that not only were they super helpful, they were a few steps ahead of us in figuring out how to reduce their own carbon footprint and impact on the environment.

The chemicals to color the glass come from all over the world, but most of the bulk raw materials (sand), come from relatively nearby in the northwest U.S. - minimizing shipping.

And in the past few years they’ve put in a couple new systems designed to reduce the impact of glass manufacturing. The first is a liquid oxygen system. Natural gas is burned to produce heat to melt glass. In order to burn, the hydrocarbons of the gas are reacting with the oxygen in the air. But oxygen is only about 21% of air, so a lot of what gets heated and reacted is nitrogen. By using pure oxygen instead of ambient air, much less natural gas is needed, and much less nitrous oxide pollution is produced. See this explanation from the EPA According to Bullseye, this system “will eventually reduce our carbon emissions by as much as 40%, and our nitrous oxide emissions by more than 90%.”

The next cool thing is the cooling system. In 2004 they switched to a recycling water cooling system, cutting their water use by more than half.

Other enviro-friendly things they do are encouraging employees not to commute by car, and internal recycling (using the ends of glass sheets to make things that are supposed to be in small pieces, like frit, and lumping broken bits together to make black glass).

So, although we’ve been using Bullseye for the colors and quality of glass, it seems like they’re a pretty good choice from an environmental standpoint too.

How does this add up for Sundrops?
To figure the impact of the glass we start out with, we took the carbon footprint of glass production, and combined it with the costs of shipping the raw materials and finished glass. Bullseye provided us with precise numbers for their glass production. I can’t publish them here because they’re a trade secret, but have used them in my own calculations.

Shipping Footprint
The best info I was able to find actually came from a study on the impacts of food transportation in Iowa from the Leopold Center for Sustainable Agriculture

They broke up transport into big, small, and medium trucks, and looked at how much they carried and what their fuel mileage was. It ends up being more efficient to carry stuff in big trucks.


Gas it takes to move 1000 pounds of stuff 1000 miles
in different trucks. I don’t know exactly what size truck my glass moves in, but it seems safe to assume that relatively big trucks are moving raw materials, and moving large chunks of glass, and relatively small trucks are involved at the end of the chain, bringing glass to my local store: Seattle Stained Glass.

The ever helpful Energy Information Administration has a page giving the CO2 emissions for different fuel types

Carbon Footprint of Glass
Plugging in the different kinds of fuel (natrual gas to melt glass, diesel to move it around), and the distances, I get a carbon footprint of 4 pounds CO2 per pound of glass. This is the impact of the glass when I pick it up from the store (I walk to and from the stained glass store, so I’m not counting any extra transport cost there), before we melt it into earrings.

Luckily, the amount of glass in a pair of earrings is pretty small. Based on this number, the glass in a thousand pairs of Sundrop earrings is responsible for about 7 pounds of carbon dioxide emissions. One flaw in this calculation is that it doesn’t account for any breakage or waste of glass on our end, between buying the glass and the final product. I suspect the number is closer to 10 pounds of CO2 per thousand pairs of earrings, but I’ll get a better number for that soon. On the other side, I’m not including our use of recycled glass (about 10%), which will make that number smaller.

Sundrop Jewelry’s footprint comes from glass, silver, plastic, paper, manufacturing, and sales. I’ve got the number for glass. What will the rest be? Where’s the easiest place to cut the impact?

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What is a pair of sundrops made of ?
Well, a scientific scale and some quick calculations tell me that a pair of sundrop earrings weighs about 3.6 grams. Of that, 22% is glass (the sundrops), 15% is silver (wire wrapping and ear hooks), 4% is plastic (ear nuts), and 59% is paper (display cards). I never realized it was quite that much paper! But I’ll have to get back to that later. Today, I’m going to talk a bit about glass.


22% glass, 15% silver,
4% plastic, 59% paper We work mostly with colored sheet glass we buy from the Bullseye Glass Company, via Seattle Stained Glass. We also use recycled bottle glass for some colors.

Where does glass come from?
The main ingredient in glass is sand, which usually makes up two thirds to three quarters of its weight. Sand, obviously, can come from just about anywhere, but not all sand is suitable for making glass. To make clear transparent glass, you need especially pure silica sand - sand that’s mostly quartz. This sand is generally mined from sandstone quarries, mostly in the midwest (home of the St. Peter sandstone). Apparently, the U.S. has quite a lot of this sort of sand, and we’re the world’s largest producer and consumer of industrial sand and gravel. I’m not sure what the environmental impacts of sand mining are - stay tuned for a later episode.
 
Stained glass starting materials and
bottle glass starting materials. The beauty of our government bureacracy is that it gives all industries a fancy designation and code (the North American Industry Classification number for “flat glass manufacturing” is 327211), and then tracks all sorts of things about them.

The Energy Information Administration (part of the Department of Energy), does this pretty cool thing called the “Manufacturing Energy Consumption Survey”, where they compare the energy usage of different industries.

Looking here, I can find that flat glass uses 63 trillion Btus of energy per year (or 18 billion kilowatt hours), which is about 0.3% of the total manufacturing energy usage in the country. By itself, that doesn’t tell me a whole lot. So I decided to compare it to some other industries. The least energy intensive industry on the list is “leather goods” at only 7 trillion Btus. The most energy intensive is “petroleum refineries” at about 6,400 trillion Btus. But this isn’t really a fair comparison. After all, we use a whole lot more petroleum than leather.

Luckily, they also have done a comparison that looks at energy usage per dollar value of the final product. Basically, this lets you compare industries without worrying about their relative size.

Flat glass uses 22.5 thousand Btus of energy per dollar of glass produced.


energy use - selected industries How does this compare to other industries?
The best performers here, interestingly, are “computer and electronic products” and “tobacco”, both of which come out at 0.5 thousand Btus of energy per dollar of product. Both of these industries make relatively small and expensive things. If you sell a computer for $2000, it doesn’t take much energy to make each dollar - most of the costs will reflect things like labor.

The worst performers here are fertilizers. “Lime” (used for fertilizer, cement, and other things) comes in at a whopping 102 thousand Btus per dollar, and “Nitrogenous fertilizers” at 59 thousand Btus per dollar. Which makes me think that when oil starts running out, one of the big things we’re going to need to worry about is our food supply.


energy use per dollar -
selected industries Glass is actually pretty high up on this list - number 17 of about 70 industries. Since the raw materials of glass are pretty cheap (sand), and there’s not a lot of labor involved in the process of making it, most of what goes into a sheet of glass is a whole lot of heat. Glass is heated up to between 2300 and 2800 degrees farenheit in the manufacturing process, a couple hundred degrees of which can be saved by using recycled glass (re-melting glass takes slightly less energy than the initial reaction with raw ingredients). Here are a couple links describing the window glass manufacturing process and the container glass manufacturing process

Carbon footprint of glass making
The carbon footprint of an industry comes from both its energy usage, and where it gets that energy. Glass manufacturing uses mostly natural gas furnaces (83%) for its heat, which makes it relatively carbon intensive.

Another interesting page from the Energy Information Administration tells us the carbon emissions and “carbon intensity” for different industries. This one’s a bit out of date (1994), but still interesting. Glass is part of the “stone, clay, and glass” sector, which emits about 6% of the total carbon emissions from manufacturing.


Energy use and carbon
footprint of glass manufacturing But if you break that up into its component parts, you’ll find that most of those emissions come from cement. The flat glass industry puts about 1 million metric tons of CO2 into the air in 1994, out of a total of 372 million metric tons from all U.S. manufacturing industries.

Of course, all this interesting stuff is general to the whole U.S., and mostly reflects big manufacturers of window glass, rather than small manufacturers of art glass. In my next post (or whenever they end up replying to me), I’ll try to follow the raw materials and energy use of a sheet of Bullseye Glass specifically.

And because I’m totally shocked to find out that paper is over half the weight of a pair of earrings, I’m planning to start in on the impact of the paper in our display cards.

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