This story from Advancing Green Chemistry, a group dedicated to finding healthier alternatives to harsh chemicals, concerns a research article in June 2010 studying the toxicity of polypropylene plastic used in sutures and hernia and transvaginal mesh.

A study out of Austria and the Institute of Analytical Chemistry states that the amount of stabilizers in commercial petroleum-based plastics used in polypropylene (PP) are usually undercounted.

Besides medical devices such as transvaginal and hernia mesh, PP is commonly used to make plastic blinds and indoor-outdoor carpets. Talc–filled polypropylene can be found in household appliances and car parts, syringes, test tubes and other medical equipment. Even the hula hoop was made of Marlex, the commercial name for polypropylene.Its cost-to-performance ratio is one of the determining factors for its use over alternatives, such as polycarbonate and polystyrene, according to the chemical consultancy group, Frost & Sullivan.

Polypropylene Under Heat

The study states that upon heating, the additives break down, especially when they are combined with talc, a common mineral filler. The concern is the chemicals migrating out of the plastic could make their way into humans. In terms of molecular structure the researchers said the newly discovered chemicals were similar to BHA and BHT, synthetic chemicals found in many products such as cosmetics, food, pharmaceuticals and lubricants which are reactive in the human body. BHA is regarded as mimicking estrogen and BHT can cause tumors and mutations in test animals.

Even the lids on Tic-Tacs packaging are made from polypropylene.

Even the lids on Tic-Tacs packaging are made from polypropylene.

It is the presence of talc that seems to encourage the breakdown of the additives at 239 degrees Fahrenheit. Polypropylene alone is known to melt above 266 degrees Fahrenheit. The scientists conclude further study is needed on the resulting chemicals from heated PP.

During the recent transvaginal mesh trial of Donna Cisson who sued C.R. Bard over its defective transvaginal mesh, her physician said he didn’t know the company had been warned not to use polypropylene resin to make implantable medical devices. That information was contained in the Material Safety Data Sheet (MSDS) that was uncovered in the discover process pre-trial.

Executives for Bard knew the resin they were using was not intended for medical implants and discuss not revealing that to the source of the raw material, Chevron Phillips.

The warning for Marlex said:

“Do not use this … material in medical applications involving permanent implantation in the human body or permanent contact with internal body fluids or tissues.”

PP was said to be inert in the body and that’s why it continues to be used in medical devices. Still with about one million hernia mesh implants which use primarily synthetic or polypropylene mesh as well as the extensive use of polypropylene-based transvaginal mesh, the real life clinical trials will be the final word on the stability of polypropylene in the human body.