Common materials that water bottles are made of include plastics, metals, and glass. Each of these materials has advantages and disadvantages when making a safe water bottle.

Plastic

Most water bottles are made of plastic. Plastic is a petroleum-based resin that is popular with water bottle manufacturers because it is easily molded or extruded. Most of today’s water bottles are made of synthetic, inorganic materials such as poylethelene and thermoplastic poymers such as polycarbonite.

Unfortunately, plastics may be the worst choice for safe water bottles. Plastic is light but can leach harmful chemicals into the water or liquid stored in it. Leaching is acceletrated when the plastic is scratched. It can also be accelerated by boiling and the use of harsh detergents.

Some of the chemicals that leach from plastic interfere with hormones and have been linked to increased risk of birth defects, cancer, miscarrage, decreased testosterone in men, and developmental problems in children.

Glass

Although glass is an excellent material for a safe water bottle because it is inert and doesn’t react with liquids, it is heavy. The obvious shortcoming of glass as a water bottle is that it is fragile. This problem can minimized by a zippered foam wrapper.

Metals

The two main metals that water bottles are made of are aluminum and stainless steel.

Aluminum is the most abundant metal on earth. We get a lot of aluminum from aluminum cookware, over the counter pain killers, anti-inflammitory pain killers and antiacids. It can also be found in baking powders, antipersperants, bleached flour, table salt, beer and tap water. This abundance of aluminum is the biggest problem when it comes to safe water bottles.

Aluminum is a toxic metal that can impair liver and kidney function, accumulate in the brain, and can cause dizziness, tiredness and balance problems. Most aluminum water bottles have an epoxy inner liner. Some of these liners may be toxic as well.

A better choice for a safe water bottle is stainless steel. Stainless steel doesn’t leach, doesn’t easily stain and doesn’t interact with the products stored in it.

Another advantage stainless steel has as a safe water bottle is that it is difficult to break. It is recyclable, lightweight, durable and doesn’t alter the taste of its contents. It is chemical free and safe to use with hot liquids. Although some people complain of a metallic taste with a new stainless steel water bottle, it can be soaked in a distilled vinegar and water solution overnight to remove the taste. Stainless steel can be cleaned with baking soda and distilled vinegar or by shaking vinegar soaked rice in the water bottle.

So your best choice for a safe water bottle is stainless steel. Glass comes in a close second. You should stay away from aluminum or plastic as they are the worst choices if you are looking for a safe water bottle.

What we know for sure about SIGG water bottles is that the exterior is made of aluminum while the interior is lined with a “water based epoxy resin.” The liner is added to prevent the aluminum from leaching into the contents of one’s water bottle since consuming aluminum has been proven to cause such health problems as Alzheimer’s and Lou Gehrig’s disease.

This liner is what makes it very difficult to answer the question, are SIGG water bottles safe? due to many unknowns about the liner. According to SIGG’s website “the ingredients (like the formula for Coca-Cola) remain secret and unavailable to 3rd parties so as to ensure SIGG retains its competitive advantage. The key of course is that the SIGG liner is FDA approved and independently tested to be taste and scent inert – and resistant to any leaching (0.0%) so 100% safe.” There are three problems with these statements: 1) the last time I checked, the ingredients for Coca-Cola are right on the can; 2) the FDA has approved many plastic and canned food products that contain Bisphenol-A (BPA), a chemical which simulates estrogen and in animal studies has been shown to cause a wide range of health problems; and 3) the 0.0% leaching they are referring to is from an “independent” study in which SIGG paid Alliance Technology LLC, a for profit company, to conduct.

In this study, the testers used an LOQ (limit of quantization) of 2 PPB (parts per billion) which basically means that they didn’t attempt to detect BPA below this level. In the scientific world, the LOQ can be considered zero. This allowed SIGG to legally (or should I say, deceptively) claim that their bottles leach no BPA.

This liner, which was the focus of the study, at one time was described as a “water based epoxy resin” by SIGG. Those words have now been removed from their website, but it continues to be displayed on product web sites such as Amazon.com. According to Wikipedia “most common epoxy resins are produced from a reaction between epichlorohydrin and bisphenol-A.” Another interesting fact is that BPA epoxy resins were co-invented by Dr. Pierre Castan of Switzerland, the same country in which SIGG bottles are manufactured. Dr. Castan’s work was then licensed by Ciba, Ltd. of Switzerland which is now one of the three major epoxy resin producers in the world.

In summary, we have learned: 1) the liner is made of a “water based epoxy resin”; 2) most epoxy resins contain BPA; 3) BPA epoxy resins were co-invented by a Swiss scientist; 4) one of the three largest manufacturers of epoxy resins is a Swiss company; 5) SIGG bottles are manufactured in Switzerland; 6) SIGG paid a for-profit lab to do an “independent” study where not all levels of BPA were tested; 7) SIGG has deceptively used this study to claim their bottles do not leach any BPA; and lastly 8) at one time they described the liner as a “water based epoxy resin” on their website, but it has since been removed. At this point you may still be asking yourself, are SIGG water bottles safe? The reality is that there isn’t enough information to say for sure. Until SIGG releases more information, you are going to have to use your best judgment to decide if you want to believe what SIGG is marketing and take the risk of your water bottle leaching a dangerous chemical such as BPA. In my opinion, I would rather go with a stainless steel water bottle, such as Klean Kanteen, which has been proven to be safe and doesn’t leach any chemicals.

Facts taken from Wikipedia

Plastic is not the harmless compound that it once appeared to be. It does not degrade readily, and is one of the most durable pollutants on earth. Over hundreds of years, plastic disintegrates into smaller and smaller pieces of plastic which eventually enter the food chain, unchanged. In 2005, 28 million tons of plastic waste were produced in the US alone. The Great Pacific Garbage Patch is an example of what happens to all our plastic cups, bottles and bags – it is a stretch of plastic waste several million square kilometers in size. It is not just the environment that suffers. Plastic releases chemicals when scratched and heated, or when it comes in contact with acidic substances. One of these chemicals is Bisphenol A (BPA), an important component of plastic water bottles, baby bottles, inner lining of food cans, microwave containers, and hundreds of common household and industrial products. The use of BPA-containing plastic in the packaging of food and beverages is alarming because there is a long list of health disorders attributed to the chemical.

BPA is a chemical compound that has a structure similar to the hormone estrogen. It sets off a chain reaction of estrogen responses in the male and female body, such as breast cell growth, regulation of the menstrual cycle, and a wide range of normal body development and functions. BPA upsets the balance of hormonal messages in the body. Hundreds of scientific studies have shown that BPA is linked to developmental and reproductive abnormalities, cancer, and even neurological disorders in animal models. In humans, the compound has been found to be linked to early onset of puberty, breast, uterine and prostate cancer, obesity and diabetes. By far the most common finding is that BPA in low doses is toxic during fetal and infant development. Pregnant women who were exposed to BPA had a higher than normal rate of birth defects and fetal and neonatal deaths.

Although BPA is only lethal at very high doses, increasing scientific evidence suggests that it can disrupt key body functions at very low doses, and builds up in our bodies over time with each exposure. Despite the multiple scientific studies that clearly link BPA to developmental and other abnormalities in animals and humans, the US Food and Drug Administration (FDA) issued a statement on August 15, 2008 reaffirming the safety of products containing low levels of BPA. However, no mention is made of the effects of repeated exposure over many years, or of the effect of combinations of hormones and BPA.

There are billions of people around the world who drink water from plastic bottles every day. Unfortunately, bottled water is harmful to the environment, your wallet and your health. Ironically, people who buy bottled water in an effort to improve overall well-being are actually putting their health at risk. BPA and other toxic chemicals have been shown to leach out of both single-use and reusable plastic water bottles. Repeated use of plastic bottles has been shown to increase the rate of chemicals like BPA leaching out, especially bottles intended for single use.

By far, the most common types of water bottles in use today are the single use and re-usable plastic bottles such as Aquafina and Nalgene. Examining the recycling labels on the base of the bottle can help determine which bottles to avoid altogether. Bottles marked with “#1” should only be used once. Bottles marked “#7”, also called Lexan, should be avoided altogether, as they definitely release BPA into the liquid. Bottles marked “#3” can also release BPA. Types 2, 4, 5 and 6 are the safer choices. However, it is safest to avoid plastic bottles altogether.

The only water bottles that are 100% safe to use are made of glass, but since glass is breakable and rather heavy, it does not appear to be a practical alternative. Fortunately, other types of water bottles are available. One common alternative is the Sigg brand of water bottle, made from aluminum with a water-based epoxy inner liner. Although Sigg bottles are recyclable, and claim they do not contain BPA, they are made of aluminum, a toxic metal. If the bottle cracks, for example due to mishandling, the aluminum can get into the liquid. Ingestion of aluminum can lead to many serious health problems, including bone and tissue damage and neurological disorders.

Another downside to the Sigg aluminum bottle is the fact that the chemicals used in making the epoxy inner liner are not divulged by the company, but kept as a trade secret. It may be best to assume that this liner is as toxic as plastic, especially since epoxy normally contains BPA. Although Sigg has released a study saying their liner is BPA free, it is quite likely to be biased since the study was paid for by Sigg. It should also be pointed out that even though the Sigg study claims that their liner is BPA free, they didn’t test for BPA levels below 2 parts per million, thus, invalidating their results and claim that their product is BPA free. This type of deception makes consumers wary of Sigg water bottles.

One last fact that should be considered in the use of aluminum for water bottles is their possible negative impact on the environment. This is because the production of aluminum requires extensive energy, much more than various other materials used for water bottles.

So what material then is the safest and least harmful to the environment? Stainless steel! Stainless steel water bottles, such as Klean Kanteen, are much more likely to be a better alternative to plastic, glass or aluminum bottles. Stainless steel bottles are 100% recyclable, durable, do not alter the taste of ones contents and almost as lightweight as plastic. More importantly, stainless steel water bottles are also free from chemicals like BPA, and are safe to use with hot liquids.

Until further tests can be carried out to determine which, if any, plastic bottles can be used without long term risks, it is better to be cautious, and utilize stainless steel water bottles in order to avoid exposure to BPA or other chemicals that may pose a risk to one’s health.