A ubiquitous chemical called Bisphenol A, better known as BPA, coats the inside of many
food and drink cans. This lining is 2 micrometers thick, less than
1/8th of the thickness of a human hair. It’s the crucial barrier between metal and
liquid that ensures a can of soda will retain it’s fizz and flavor.
Because it’s cheap, durable, and flexible,
BPA is a key building block of the plastics we use.
But there are significant health concerns related to BPA.
A lab at Sherwin-Williams, a company better known for paint, has come up with an alternative.
BPA has been linked to breast and prostate cancer, and reduced fertility.
Studies have shown that it mimicks the hormone estrogen--which influences growth and development,
and it disrupts other endocrine processes. Meanwhile, In the 2000’s the CDC found BPA
in the urine of 93% of U.S. adults tested.
A public backlash to the use of BPA has ensued. Today, certain BPA products are banned in many countries.
Companies have sought a good replacement for BPA as a can liner... but have struggled.
Vinyls and acrylics have shorter shelf lives or require more coatings.
Some other Bisphenols come with the same concerns as BPA.
But researchers at Sherwin Williams came up with an idea:
What if they could stick with a bisphenol, but find one that wasn’t an endocrine disruptor like BPA.
Company scientists started out with a computer program. It screened hundreds of different
bisphenols, searching for molecular structures that appeared unlikely to bind with the body’s estrogen receptors.
The team found a promising molecule: Tetramethyl Bisphenol F (TMBPF), a rarely used chemical
once considered for helping build electronic circuit boards.
Research suggests that one of the advantages of TMBPF is that it doesn’t leak from can
linings into drinks like BPA does. Next, Sherwin-WIlliams wanted proof that the chemical was benign.
The company wanted to establish the molecule’s safety--
and protect its research investment.
So the developers decided that they should let outside scientists and consumer advocates
in on the process.
The lab reached out to Ana Soto, an endocrinologist well-known for raising concerns about BPA’s
health effects. She put the chemical through a battery of tests.
Her lab found that TMBF: Didn’t activate estrogen receptors or spur
growth of breast cancer cells.
And didn’t affect several genes that respond to estrogen.
Sherwin Williams has taken a hands-off approach
so that Soto could study the chemical however she saw fit.
This has added legitimacy to the research in the eyes of the broader community.
Another scientist reviewed test data and organ samples and concluded that TMBPF doesn’t
seem to affect the thyroid system.
But it wasn’t all good news.
One scientist found that TMBPF might blunt the effect of estrogen on tests cells and
that a polymer made from the molecule might have similar effects on testosterone.
However, a lead researcher in the study said the findings weren’t conclusive and could
be specific to these cells. Environmentalists are cautiously encouraged
about TMBPF but they aren’t assured that it is safer than other options.
Something as complex as the endocrine system
has made a definitive safety screening out of reach so far.
Still, other scientists are working on more tests and Sherwin-Williams is preparing to
launch a new study to answer some of the remaining questions.
Meanwhile, the company has already started selling a TMBPF-based can coating, branded as V70.
The company says that since 2017, it’s product has been used on 22 billion cans.
Still a modest fraction of the estimated 450 billion cans produced each year worldwide.
Regardless of public health concerns, the bottom line might be what determines the adoption of V70.
It’s currently twice the price of BPA, though
company officials say this is comparable to other non-BPA linings.
It remains to be seen whether or not both industry and consumer groups will ultimately
deem the chemical to be safer. Either way, the price tag could keep this
BPA alternative from becoming as popular as BPA once was.