Ten-week Whole-body Inhalation Toxicity Study of Chlorine Dioxide Gas in Rats

1,1,2,2-Tetrafluoroethane (HFC-134) is a colorless gas used as a foam expansion agent and heat transfer fluid. HFC-134 has a low acute inhalation toxicity with an LC50 of >244,000 ppm. The no-observed adverse effect level (NOAEL) and lowest-observed adverse effect level for cardiac sensitization (in epinephrine-challenged beagle dogs) were 75,000 and 100,000 ppm, respectively. A subacute 4-week GLP inhalation toxicity study exposed male and female Crl: CD®BR rats (10/sex) to 0, 2000, 10,000, or 50,000 ppm via whole-body inhalation. Transient and non-dose-response–related body weight changes were observed throughout the exposure period, but no statistically significant, test substance-related adverse effects were observed in any clinical observations, chemistry, hematology, or pathology. This study identified a NOAEL for HFC-134 of 50,000 ppm, the highest exposure level tested. HFC-134 is not genotoxic in in vitro studies; however, no in vivo studies are available. No developmental or maternal toxicity was found in female rats exposed to HFC-134 up to 50,000 ppm via whole-body inhalation in two different studies. Based on data for a similar material (HFC-134a), HFC-134 is not expected to be extensively metabolized or to cause genetic toxicity or carcinogenicity. The HFC-134 workplace environmental exposure level (WEEL) is based primarily on the subacute 4-week inhalation toxicity study in rats with the NOAEL of 50,000 ppm selected as the point of departure for the derivation of the 8-h TWA, health-based WEEL value. The developmental toxicity study also had a NOAEL of 50,000 ppm and was the highest exposure level tested. The subacute inhalation NOAEL was adjusted to account for interindividual variability, subacute to chronic duration, animal to human extrapolation, daily duration of exposure, and residual uncertainty. In addition, the lack of adverse effects noted in the toxicology studies for HFC-134a was considered. The resulting 8-h TWA WEEL value of 1000 ppm is expected to provide a significant margin of safety against the production of any potential adverse health effects in workers following long-term inhalation exposure to HFC-134.

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Six-month low level chlorine dioxide gas inhalation toxicity study with two-week recovery period in rats

Journal of Occupational Medicine and Toxicology ◽

10.1186/1745-6673-7-2 ◽

2012 ◽

Vol 7 (1) ◽

pp. 2 ◽

Cited By ~ 6

Author(s):

Akinori Akamatsu ◽

Cheolsung Lee ◽

Hirofumi Morino ◽

Takanori Miura ◽

Norio Ogata ◽

...

Keyword(s):

Chlorine Dioxide ◽

Recovery Period ◽

Toxicity Study ◽

Inhalation Toxicity ◽

Low Level ◽

Chlorine Dioxide Gas ◽

Gas Inhalation

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Respiratory Safety Evaluation in Mice and Inhibition of Adenoviral Amplification in Human Bronchial Endothelial Cells Using a Novel Type of Chlorine Dioxide Gas Reactor

Toxics ◽

10.3390/toxics10010038 ◽

2022 ◽

Vol 10 (1) ◽

pp. 38

Author(s):

Hae-Sung Yang ◽

Kyeong-Min Kim ◽

Napissara Boonpraman ◽

Sun-Mi Yoon ◽

Jeong-Eun Seo ◽

...

Keyword(s):

Chlorine Dioxide ◽

Viral Infections ◽

Recombinant Adenovirus ◽

Safety Evaluation ◽

Control Group ◽

Inhalation Toxicity ◽

Bronchial Epithelial ◽

Chlorine Dioxide Gas ◽

New Type ◽

Inhibitory Power

Since the onset of the COVID-19 pandemic, there has been a growing demand for effective and safe disinfectants. A novel use of chlorine dioxide (ClO2) gas, which can satisfy such demand, has been reported. However, its efficacy and safety remain unclear. For the safe use of this gas, the stable release of specific concentrations is a must. A new type of ClO2 generator called Dr.CLOTM has recently been introduced. This study aimed to investigate: (1) the effects of Dr.CLOTM on inhibiting adenoviral amplification on human bronchial epithelial (HBE) cells; and (2) the acute inhalation safety of using Dr.CLOTM in animal models. After infecting HBE cells with a recombinant adenovirus, the inhibitory power of Dr.CLOTM on the virus was expressed as IFU/mL in comparison with the control group. The safety of ClO2 gas was indirectly predicted using mice by measuring single-dose inhalation toxicity in specially designed chambers. Dr.CLOTM was found to evaporate in a very constant concentration range at 0–0.011 ppm/m3 for 42 days. In addition, 36–100% of adenoviral amplification was suppressed by Dr.CLOTM, depending on the conditions. The LC50 of ClO2 gas to mice was approximately 68 ppm for males and 141 ppm for females. Histopathological evaluation showed that the lungs of female mice were more resistant to the toxicity from higher ClO2 gas concentrations than those of male mice. Taken together, these results indicate that Dr.CLOTM can be used to provide a safe indoor environment due to its technology that maintains the stable concentration and release of ClO2 gas, which could suppress viral amplification and may prevent viral infections.

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