AN EPIDEMIC OF POLYMER-FUME FEVER

The Devil they Knew: Chemical Documents Analysis of Industry Influence on PFAS Science

Background

Per-and polyfluoroalkyl substances (PFAS) are a class of widely-used chemicals that persist in the environment and bioaccumulate in humans and animals, becoming an increasing cause for global concern. While PFAS have been commercially produced since the 1940s, their toxicity was not publicly established until the late 1990s. The objective of this paper is to evaluate industry documents on PFAS and compare them to the public health literature in order to understand this consequential delay.

Methods

We reviewed a collection of previously secret industry documents archived at the UCSF Chemical Industry Documents Library, examining whether and how strategies of corporate manipulation of science were used by manufacturers of PFAS. Using well-established methods of document analysis, we developed deductive codes to assess industry influence on the conduct and publication of research. We also conducted a literature review using standard search strategies to establish when scientific information on the health effects of PFAS became public.

Results

Our review of industry documents shows that companies knew PFAS was "highly toxic when inhaled and moderately toxic when ingested" by 1970, forty years before the public health community. Further, the industry used several strategies that have been shown common to tobacco, pharmaceutical and other industries to influence science and regulation - most notably, suppressing unfavorable research and distorting public discourse. We did not find evidence in this archive of funding favorable research or targeted dissemination of those results.

Conclusions

The lack of transparency in industry-driven research on industrial chemicals has significant legal, political and public health consequences. Industry strategies to suppress scientific research findings or early warnings about the hazards of industrial chemicals can be analyzed and exposed, in order to guide prevention.

Rapid Determination of Per- and Polyfluoroalkyl Substances (PFAS) in Harbour Porpoise Liver Tissue by HybridSPE®-UPLC®-MS/MS

A rapid hybrid solid phase extraction (HybridSPE®) protocol tailored to ultra-performance liquid chromatography-electrospray ionization tandem mass spectrometry (UPLC®-ESI-MS/MS) analysis was developed for the determination of 15 per- and polyfluoroalkyl substances (PFAS) in liver tissue from harbour porpoises (Phocoena phocoena). The HybridSPE® technique has been applied in trace concentration bioanalysis, but it was mainly used for liquid biological media until now. In this study, the protocol was applied on tissue matrix, and it demonstrated acceptable absolute recoveries (%) ranging from 44.4 to 89.4%. The chromatographic separation was carried out using a gradient elution program with a total run time of 4 min. The inter-day method precision ranged from 2.15 to 15.4%, and the method limits of detection (LODs) ranged from 0.003 to 0.30 ng/g wet weight (w.w.). A total of 20 liver samples were analyzed to demonstrate the applicability of the developed method in liver tissue from a wildlife species.

Airborne nanoparticle concentrations in the manufacturing of polytetrafluoroethylene (PTFE) apparel

One form of waterproof, breathable apparel is manufactured from polytetrafluoroethylene (PTFE) membrane laminated fabric using a specific process to seal seams that have been sewn with traditional techniques. The sealing process involves applying waterproof tape to the seam by feeding the seam through two rollers while applying hot air (600 °C). This study addressed the potential for exposure to particulate matter from this sealing process by characterizing airborne particles in a facility that produces more than 1000 lightweight PTFE rain jackets per day. Aerosol concentrations throughout the facility were mapped, breathing zone concentrations were measured, and hoods used to ventilate the seam sealing operation were evaluated. The geometric mean (GM) particle number concentrations were substantially greater in the sewing and sealing areas (67,000 and 188,000 particles cm⁻³)) compared with that measured in the office area (12,100 particles cm⁻³). Respirable mass concentrations were negligible throughout the facility (GM = 0.002 mg m⁻³) in the sewing and sealing areas). The particles exiting the final discharge of the facility's ventilation system were dominated by nanoparticles (number median diameter = 25 nm; geometric standard deviation of 1.39). The breathing zone particle number concentrations of the workers who sealed the sewn seams were highly variable and significantly greater when sealing seams than when conducting other tasks (p < 0.0001). The sealing workers' breathing zone concentrations ranged from 147,000 particles cm⁻³ to 798,000 particles cm⁻³, and their seam responsibility significantly influenced their breathing zone concentrations (p = 0.03). The finding that particle number concentrations were approximately equal outside the hood and inside the local exhaust duct indicated poor effectiveness of the canopy hoods used to ventilate sealing operations.

Pulmonary effects induced by ultrafine PTFE particles

PTFE (polytetrafluoroethylene) fumes consisting of large numbers of ultrafine (uf) particles and low concentrations of gas-phase compounds can cause severe acute lung injury. Our studies were designed to test three hypotheses: (i) uf PTFE fume particles are causally involved in the induction of acute lung injury, (ii) uf PTFE elicit greater pulmonary effects than larger sized PTFE accumulation mode particles, and (iii) preexposure to the uf PTFE fume particles will induce tolerance. We used uf Teflon (PTFE) fumes (count median particle size approximately 16 nm) generated by heating PTFE in a tube furnace to 486 degrees C to evaluate principles of ultrafine particle toxicity. Teflon fumes at ultrafine particle concentrations of 50 microg/m(3) were extremely toxic to rats when inhaled for only 15 min. We found that when generated in argon, the ultrafine Teflon particles alone are not toxic at these exposure conditions; neither were Teflon fume gas-phase constituents when generated in air. Only the combination of both phases when generated in air caused high toxicity, suggesting either the existence of radicals on the surface or a carrier mechanism of the ultrafine particles for adsorbed gas compounds. Aging of the fresh Teflon fumes for 3.5 min led to a predicted coagulation to >100 nm particles which no longer caused toxicity in exposed animals. This result is consistent with a greater toxicity of ultrafine particles compared to accumulation mode particles, although changes in particle surface chemistry during the aging process may have contributed to the diminished toxicity. Furthermore, the pulmonary toxicity of the ultrafine Teflon fumes could be prevented by adapting the animals with short 5-min exposures on 3 days prior to a 15-min exposure. Messages encoding antioxidants and chemokines were increased substantially in nonadapted animals, yet were unaltered in adapted animals. This study shows the importance of preexposure history for the susceptibility to acute ultrafine particle effects.

Pulmonary toxicity following exposure to an aerosolized leather protector

BACKGROUND

An aerosol spray for leather protection was reformulated to remove trichloroethane. The new formulation contained isobutane, n-heptane, ethyl acetate and fluoroaliphatics.

RETROSPECTIVE REVIEW

Thirty-nine patients reported symptoms to the regional poison center. Respiratory symptoms developed within hours of exposure. Most symptoms resolved within two days. Abnormal pulmonary function tests, including obstructive disease or diminished diffusing capacity, were demonstrated in three of the four tested patients.

CONCLUSIONS

The mechanism for the pulmonary toxicity has not been determined.

The resistance to carbon dioxide laser ignition of a new endotracheal tube: Xomed Laser-Shield II

STUDY OBJECTIVE

To assess the resistance of a new endotracheal tube to penetration and ignition by a carbon dioxide (CO2) laser at a clinically relevant power setting.

DESIGN

An unblinded, in vitro trial simulating clinical conditions.

SETTING

The operating room at a university medical center.

PATIENTS

None.

INTERVENTIONS

A CO2 laser at 20W with a beam diameter of 1 mm was directed onto the Xomed Laser-Shield II at several points: both perpendicular and tangential to the portion of the tube covered by the protective wrap, to the unwrapped silicone tubing just proximal to the cuff, to the cuff filled with saline and methylene blue, and to the unwrapped silicone tubing distal to the cuff. Trials were performed with or without supplemental oxygen (O2) blown onto the study site and with a 6 L/min flow through the tube containing one of four concentrations of O2 in O2-air admixtures: 21%, 30%, 40%, and 100%.

MEASUREMENTS AND MAIN RESULTS

Under all conditions, the laser did not penetrate the protective wrap, but the overlying polytetrafluoroethylene (Teflon) sheet was vaporized to an area equal to the size of beam application. The cuff was penetrated by the laser within 5 seconds. The unprotected silicone protein of the tube was penetrated by the laser in approximately 5 seconds, and time to formation of a blowtorch phenomenon shortened with increasing the percentage of O2 flowing through the tube.

CONCLUSIONS

The protective coating of the Xomed Laser-Shield II is laser-resistant, but the unprotected silicone proximal and distal to the cuff is laser-vulnerable and can, under certain conditions, promote a blowtorch phenomenon. This tube would be acceptable for use in oral and pharyngeal laser surgery, but we recommend its use only in well-ventilated areas, out of concern for exposure to the products of the pyrolysis of Teflon, specifically the development of polymer-fume fever.

Fever of unknown origin

The evaluation of an FUO is a significant test of all a physician's clinical skills. The ultimate goal of the physician is to reach a diagnosis and to cure the patient in the best possible situation. Despite such pressure both externally and self-imposed, a physician needs to meticulously follow the patient and logically pursue the available diagnostic tests. To "shotgun" the process, except in the most urgent situation, is to ultimately create more frustration, confusion, and despair among the physician and his patient.

Prolonged fever associated with inhalation of multiple pyrolysis products

A case of smoke inhalation with a self-limited but prolonged febrile course, including headaches and chills, is reported. A final diagnosis of polymer fume fever was made, although the duration of fever was longer than generally has been reported with this syndrome. Pyrolysis products involved included those of polyurethane, methylene chloride, and polytetrafluoroethylene ("Teflon"). The results of toxicological testing are reported and discussed.