Safer Science Through Substitution: A Success Story from the Joy Lab
The U.S. Environmental Protection Agency (EPA) issued a final rule under the Toxic Substances Control Act (TSCA) to significantly reduce and regulate methylene chloride, also known as dichloromethane (DCM), in laboratories. This rule is part of the Workplace Chemical Protection Program (WCPP). The new EPA 8-hour time-weighted average (TWA) is 2 ppm, a 12.5-fold reduction from the previous OSHA limit of 25 ppm.
As of May 1, 2025, the use of DCM is prohibited in teaching labs and shops. For research labs where the use of DCM is essential to experiments, baseline exposure monitoring has been conducted by OARS and certified industrial hygienists to develop a DCM Exposure Control Plan. However, PIs and lab managers are encouraged to find safer alternatives. Click here for more information on Northeastern’s DCM policies.
The EPA’s action stems from DCM’s severe health risks. Inhalation or skin exposure can damage the central nervous system and increase cancer risk, as DCM metabolizes into carbon monoxide, a toxic asphyxiant, and formaldehyde, which is a carcinogen. To learn more about DCM’s potential public health risks, click here.
However, despite its significant health risks, DCM serves as a powerful solvent for a variety of organic compounds, making it a go-to solvent for many reactions, extractions, recrystallizations, and sample preparations. DCM is also non-flammable, unlike many organic solvents, which reduces fire hazards despite its toxicity. Additionally, DCM is frequently used in chromatography, a purification technique for chemical samples that may use DCM to dissolve materials or as an elution solvent. Though the reduction and elimination of DCM in labs is a necessary step towards worker health protection, the new regulation has presented growing pains to many labs across the country.
One laboratory that has successfully complied with the new methylene chloride regulation is Dr. Abraham Joy’s Biomaterials Innovation and Translation (BIT) lab in Northeastern’s ISEC building. The lab focuses on developing synthetic biomaterials, such as biodegradable polymers and synthetic scaffolds to support tissue regeneration, to use in critical biomedical challenges. One of the core research areas of the Joy Research Lab is the engineering of adhesive and patches for mitigating non-compressible hemorrhages, as well as developing solutions for antibiotic-resistant infections through the creation of synthetic polymers that mimic biosurfactants and disrupt bacterial biofilms. Much of the research and products produced by the Joy lab is used to mitigate civilian and military populations from suffering from uncontrollable blood loss or infection.
Methodology Adaptations in the BIT Lab
Facing both regulatory pressure and a commitment to safer laboratory practices, Dr. Joy’s BIT lab at Northeastern University decided to voluntarily phase out the use of methylene chloride in early 2025—months ahead of the May 1 deadline for teaching environments. While DCM was still technically permissible in research labs under the EPA’s new rule, the team took the proactive step of identifying and validating alternative solvents that would maintain experimental performance without compromising safety. The lab’s transition away from DCM exemplifies both the scientific and logistical challenges involved in complying with the new regulation while maintaining high standards for experimental accuracy and efficiency.
Dr. Abraham Joy, the lab’s principal investigator, reflected: “Methylene chloride has unique solubility properties for small molecules and macromolecules, and hence has been a workhorse solvent for numerous applications in academia and industry. However, the growing recognition of its safety concerns calls upon all scientists to re-evaluate their protocols with the aim to decrease or eliminate its use. I am glad that the students in our lab have managed to do that.“
Ph.D. researcher Justin Cross, who has worked extensively with polymer synthesis in the BIT Lab, explained why DCM had been so critical to the group’s polymer synthesis workflows. “We use DCM as our solvent in those reactions because a lot of our polymers are soluble in an organic solvent,” he said. “DCM also has the right polarity for us, which is why our polymers can do that. We also need the solvent to be anhydrous or dry. We don’t want any of our polymer chains to break down because the solvent takes on moisture, so DCM is a very good agent for using in our polymerization reactions.”
In response to the EPA ruling, the lab undertook a systematic solvent substitution effort. Despite DCM’s effectiveness, Cross and others in the lab recognized the necessity of adopting safer alternatives. The lab began a systematic process to identify, test, and validate replacement solvents, focusing especially on those that could replicate the unique solvation properties of DCM without the associated health risks.
After reviewing existing research and performing multiple trials, the team identified a mixture of ethanol and ethyl acetate (EA) as a functional replacement in both polymer synthesis and preparative thin-layer chromatography workflows. Cross noted the safety advantages of these replacements: “Ethanol is already pretty safe—it’s something you see on countertops in bio labs, and we even consume it socially [as alcohol]. Ethyl acetate is similar. It may have slightly worse side effects than ethanol, but both are relatively low-risk overall. That made the combination a good choice for us.”
One area of particular challenge was preparative thin-layer chromatography (TLC), where DCM had previously been the standard due to its elution efficiency and compatibility with various organic molecules. For this task, PhD. researcher Prathamesh Mane noted that switching to ethyl acetate (EA) and ethanol mixtures provided a workable solution, though not without difficulties.
“There is no one good answer for running any chromatography,” Mane said. “Ethyl acetate ethanol works fine for most of the things, and it seems to replace this DCM. The challenge is mostly about finding that optimum ethyl acetate to ethanol ratio—you have to do that for every new chemical you synthesize. It’s a bit challenging, but it’s doable.”
In addition to improving lab safety, the shift to ethyl acetate and other alternative solvents had practical benefits as well. Mane explained that, in addition to its safety benefits, EA is more accessible, less expensive, and requires less intensive waste management. “Before when we used DCM, we had to collect it in two separate waste cans and then we had to go through a separate system of disposing it. EA takes all those extra troubles away.”
While acknowledging the superior separation efficiencies offered by DCM, Mane emphasized the psychological comfort that came with eliminating the solvent from daily lab work. “DCM allows for very good separation efficiencies, but switching back to ethyl acetate actually feels a bit safer,” he said. “Now I know that I’m not getting exposed to DCM and its carcinogens.”
A Model for Safer Innovation
The BIT Lab’s success in moving away from methylene chloride stands as a model for other research groups navigating similar transitions. By systematically evaluating alternative solvents and training researchers on new methods, Joy lab was able to preserve the integrity of its cutting-edge biomaterials research while fully complying with federal safety regulations with a higher degree of safety through effective substitution with less hazardous solvents.
As chemical safety regulations continue to evolve, the experience of the BIT Lab underscores a broader principle: innovation in scientific research must go hand-in-hand with innovation in safety and sustainability. By phasing out a hazardous but historically essential solvent like DCM, the Joy Lab demonstrates that high-impact biomedical research can thrive in a safer, more responsible laboratory environment.
Has your lab replaced DCM or another high hazard chemical with a safer alternative? Share your story to oars.northeastern.edu to help others make the switch.
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