Is My PVC Pipe Dangerous?

Deb writes The Green Guide:

Our home is completely piped with PVC water piping. I cannot find any articles that tell me if this PVC is safe or not. One article, "Old Home Renovation" suggest it is not safe. Are our PVC water lines leaching phthalates into our drinking and showering water daily? Are there different grades of PVC?

Deb

The Green Guide responds:

PVC is not an environmentally sound choice for water piping: PVC is hazardous throughout its lifecycle, and PVC of all forms, from tiles to toys to blinds to pipes, contains numerous additives that are especially harmful when burned. However, to address your immediate concern, while installed in your walls or in the ground PVC pipe does not appear particularly hazardous to your health. Toxic phthalates can leach from PVC treated with softening plasticizers; PVC pipe, however, is rigid and does not present a phthalate risk. There are other additives to worry about in PVC pipe, but most evidence seems to say that you shouldn't worry too much. How old is your pipe? PVC pipe manufactured before 1977 can leach vinyl chloride into your water. Newer pipes alleviate that hazard--though Greenpeace's toxics campaigner Rick Hind isn't so sure. "That's what the industry says, but we don't know," he said. "We'll have to see how they age." More certainly, PVC pipes often contain organotins as stabilizers. These metallic compounds are immunotoxic at high levels, but leach from pipes in amounts orders of magnitude lower than is toxic; leaching is greatest at the beginning of the pipe's life. According to the World Health Organization, organotin is not a major concern in drinking water. Still, PVC pipes, though fire resistant, are as toxic as any other PVC when burning or smoldering.

When building a new house, should you install PVC? Should you replace the PVC pipes you already have--is it dangerous enough to make it worth replacing immediately?

The answer to the first question is a probable No, and you should steer clear of PVC more generally. From manufacturing to disposal, PVC has high environmental costs. Its full name is polyvinyl chloride, though it's generally known as vinyl; as the name implies, PVC contains a high percentage of chlorine--it's made with the carcinogen vinyl chloride, and dioxin and ethylene dichloride are byproducts of its manufacture. PVC is hardly recyclable and when incinerated releases both dioxin and hydrogen chloride gas. Dioxin is a very potent known carcinogen; it causes cancer and reproductive disorders, and bioaccumulates and persists in nature.

But chlorine and its dangerous compounds aren't the only problem. PVC is softened for certain uses with substances called plasticizers, stabilized and colored with heavy metals, and treated with fungicides. All these additives can be released in incineration--Greenpeace estimates that 100 toxins are released in a PVC fire. PVC is fire resistant, but smolders at lower temperatures, producing hydrogen chloride gas without visible signs of fire--a literally hidden danger. For these reasons, the International Association of Firefighters supports alternative materials to replace PVC.

PVC's additives make it dangerous during its lifespan. Plasticizers in soft PVC products (wall coverings, floor tiles, cling wrap, furniture upholstery, and toys, among others) can release phthlates such as DEHP, which can damage the reproductive systems of and have carcinogenic effects in animals, though human effects are still unclear. A study from the February 1999 issue of the American Journal of Public Health found that children raised in houses with PVC flooring were 89 percent more likely to develop bronchial obstructions. A September 1997 study in Environmental Health Perspectives also found a possible link between phthalates and asthma The EPA classifies DEHP as a probable human carcinogen. Lead and/or cadmium has been found by Greenpeace in vinyl mini-blinds and toys, though the toy results were disputed by the CPSC.

The answer to the second question is a little murkier. The alternatives to PVC pipe have their own flaws and, in many functional ways, PVC is a versatile material: it is light and strong and durable, resists corrosion, and is cheap and easy to install, though it expands and contracts in heat and cold respectively, placing strain upon joints and fixings. High-density polyethylene (HDPE) is also cheap, light, and flexible, though it, like any plastic, requires fossil fuels in its manufacture. A bigger problem for certain uses is its especially high expansion coefficient, three times higher than PVC, making it less useful for water and waste use. ABS pipe's chemical components are nearly as environmentally problematic as PVC's, ABS manufacture is energy intensive, and ABS expands more than PVC. Cast iron is durable, but heavy and thus expensive to install; it can also corrode, and requires more energy to manufacture than any other pipe. Vitrified clay has an incredibly long life, 100 years or more, though it is even heavier than cast iron; still, it requires the least energy to manufacture of any pipe and has a very low expansion coefficient.

It's a choice between imperfect solutions. While Greenpeace is clearly opposed to PVC, less political groups like Environmental Building News seem agnostic on the pipe issue. If you're already committed to replacing pipes, or are building a new hose, the lifecycle issues should steer you clear of PVC. But if your PVC pipes are new, and protected from fire, you have to weigh small leaching risks against the functional, monetary, and environmental cost of early replacement.

Alternative pipe suppliers (Courtesy Greenpeace):

Polyethylene
Advanced Drainage Systems, 800-821-6710, www.ads-pipe.com
Hancor, 888-FOR-PIPE, www.hancor.com
Chevron Phillips Driscopipe, 800-231-1212, www.driscopipe.com
CSR PolyPipe, 800-433-5632
Pyramid Industries, 814-455-7587, www.pyramidind.com
Prinsco, 800-992-1725, www.prinsco.com
Charter Plastics, 814-827-9665, www.charterplastics.com

Clay
Logan Clay Products, 800-848-2141, www.loganclaypipe.com
Can Clay. 800-282-2529, www.canclay.com
Gladding McBean, 916-645-9525, www.gladdingmcbean.com
Mission Clay Products, 909-277-4600, www.missionclay.com/

Ductile iron and stainless steel
Davidson Pipe Supply, 718-439-6300, www.davidsonpipe.com
Everett J. Precott, Inc. 207-582-1851, www.ejprescott.com