Is there evidence to suggest concern about epoxy safety?
Prior to its use in pipe-lining, epoxies have served as barrier coats in water storage vessels. This process is
much simpler than lining a pipe, but the process and chemistry are still complex, and there are many
opportunities for problems. Failures in substrate preparation, e.g., insufficient drying, errors in mixing of
ingredients, etc., may lead to problems in the finished coating, some of which can affect barrier integrity (6). An
incorrect formulation could lead to incomplete curing and the potential for chemicals to leach from the coating
into drinking water.
Water contamination from some epoxy pipe-lining materials has been found in independent laboratory tests.
Alben el al. found that methyl isobutyl ketone and xylene leached from epoxy-coated test panels and from
epoxy-lined water storage tanks [cited in (5)]. Hazardous volatile organic chemicals, among them benzene and
1
ANSI – American National Standards Institute, NSF – National Sanitary Foundation
2
For example, with the USEPA listed organic contaminants, the ANSI/NSF 61 standard requires that contaminant
levels be no more than one-tenth of the maximum level allowed in water by the USEPA or other regulating authorities.
xylene, were found to leach from epoxy into water at levels above the acceptable maximum specified by US
and Canadian regulations, and some of the tested materials were ANSI/NSF 61 certified (7). The Satchwill
report concludes, “It was found that these linings can cause significant contamination of the drinking water” (7).
The US military services have used epoxy pipe-lining since the 1990’s to deal both with high corrosion
environments aboard ships and for pipe-rehabilitation to avoid lead contamination in drinking water (8)
(9). In 1992, the Naval Research Laboratory’s (NRL) coating development program was delayed and
forced to shift to new formulations. Changes in federal regulations that year tightened restrictions on
one of the existing coating components, a toxic, carcinogenic epoxy hardener, 4,4'-methylene dianiline
(10). While the main concern was safety of the epoxy workers, the components of some epoxy systems
used for pipe rehabilitation clearly pose a potential risk for toxic chemical contamination.
In the United Kingdom (UK), epoxy-lining for pipe rehabilitation began in the 1970’s and became common-
place in the 1990’s (11). Concerned that the aging of rehabilitated piping systems might pose health hazards,
regulators commissioned a study. The 2007 report to the UK Drinking Water Inspectorate concluded that,
“...any leaching from the pipe linings is at a low level” (11). Pipes lined with five UK-approved epoxy
formulations were surveyed. The report notes that, “Evidence of leaching of 4-t-butylphenol (4-TBP) from
Resin C was found...”, however, the concentration was quite low (in the part per billion range). While 4-TBP is
an irritant, it is not otherwise believed to present a significant health risk.3 It is important to note that in the UK,
in-place epoxy-lining can only be performed by approved contractors.
Some epoxy materials used for pipe-lining are formed from the controversial bisphenol-A (BPA).
Repeated studies by the US Centers for Disease Control and Prevention have detected BPA in the
urine of 93% of tested individuals (age 6 and above) (12). BPA is an endocrine disruptor, and there are
significant concerns about the safety of chronic exposure to low-levels in food (13). While pipe-lining
suppliers say their products are safe, vendor documents acknowledge that there is some risk for
bisphenol-A exposure above ANSI/NSF 61 certification levels when lining installation procedures are
not rigorously followed (14).
Most vendor websites provide little detail on the chemical formulations of their epoxies. Even worse, there may
be serious inaccuracies, for example, the Cleanncoat site states, “...CleanncoatTM does not use any chemicals
in the pipe restoration process. We use three elements: air, sand, and epoxy” (15). There is no doubt that
chemicals, and in some cases hazardous ones, are used to produce epoxy pipe-linings. Any claim to the
contrary should be a red-flag for potential customers.
What is bisphenol A?
Bisphenol A (BPA) is a widely produced chemical used primarily for the production of polycarbonate plastics and epoxy resins. More than 6 billion pounds of BPA are produced and used each year for this purpose. The use of this chemical is so profound that it was detected in the urine in 93% of the population over 6 years of age. The study did not include anyone under 6 years of age, so the level in their urine is unknown.
Polycarbonate plastics are typically hard and clear and are marked with the resin identification code number 7. As mentioned previously, the number 7 is considered the "other" category and includes chemicals other than bisphenol A. Nalgene water bottles were made with BPA until recently. They are being voluntarily pulled from the shelves and replaced by bottles that are BPA-free made with a relatively new plastic called Tritan copolyester. Other sources of polycarbonate are food and drink packaging, including infant bottles, toddler sipping cups, tableware, and food containers. Epoxy resins are used to line metal products such as canned foods, bottle tops, and water supply pipes.
