Methylene chloride is a chemical used in paint strippers that is bad for the environment and very toxic — it can even kill you. Methylene chloride is dangerous for workers and consumers and we need safer strippers- but my new research shows the dark side of making a substitution without a careful evaluation.
My colleagues from the National Institute for Occupational Safety and Health and I recently published an article summarizing a surprising finding – after replacing methylene chloride with an alternative stripper considered to be safer and labeled a “green” product, there were actually unanticipated hazardous exposures and health effects found for workers at a commercial aircraft refinishing facility.
We documented that the new stripper product added a source of hexavalent chromium to the overall refinishing process. Hexavalent chromium is a toxic, cancer-causing metal found in the aircraft paint for rust resistance. Because the new stripper functioned differently than methylene chloride, workers had to increase sanding to remove the paint, increasing amounts of hexavalent-chromium-containing dust which the workers breathed in.
Sadly, we found significant health issues typical of the irritation effects of hexavalent chromium. Forty percent of employees had nose health issues after using this new stripper for over a year, with almost 20% already showing nasal ulcerations (i.e., lesions inside of your nose that are hard to heal and can result in a hole inside your nose).
Our findings suggest that occupational health practitioners who oversee or monitor employees exposed to hexavalent chromium should routinely check nasal health, as the nose effects may be seen even at low levels of chromium urine, like we saw in this study.
Our findings raise the questions – how do we ensure this doesn’t happen again, and that replacements for methylene chloride are safer? Currently, there is a new proposal to ban methylene chloride, but it is still sold in hardware stores. In the last year, major retailers have already dropped methylene chloride from their shelves. But any alternative methylene chloride substitution in the future clearly warrants an evaluation of such a change to assess the potential for unexpected hazards. Hexavalent chromium, for example, will not be an issue when stripping a bath tub, but it is possible other hazards may be present that workers (or the do-it-yourself home owners) are not aware of when using a new stripper — especially if this new product has not been carefully tested for safety in different scenarios.
Alternatives assessment is a process for identifying, comparing, and selecting safer alternatives to chemicals of concern on the basis of their hazards, performance, and economic viability. The primary goal of these methods is to reduce harm to human health and the environment by providing a comprehensive approach to identifying safer chemicals, making informed decisions, and avoiding regrettable substitutions. The Massachusetts Toxics Use Reduction Institute and BizNGO have both completed alternatives assessments for methylene chloride.
As we move forward with methylene chloride phase outs, we also need a clear plan forward towards testing new stripper products for health and safety, such as through comprehensive alternatives assessment, before they are used by workers or sold to the public.
About the author
Dr. Diana Ceballos is an Assistant Professor in the Department of Environmental Health, Boston University School of Public Health, and a Visiting Scientist in the Department of Environmental Health, Harvard T.H. Chan School of Public Health. She is an expert in exposure assessment of chemical mixtures related to new technologies and vulnerable populations. Dr. Ceballos was an Industrial Hygienist at the National Institute for Occupational Safety and Health (NIOSH), U.S. Centers for Disease Control and Prevention (CDC) for 5 years prior to returning to academia.
Dr. Ceballos’ co-authors include Christine West, Mark Methner, and Wei Gong. This work was supported by NIOSH/CDC, JPB Environmental Health Fellow, and NIH/NIEHS 2R25ES023635-04.