Last month, Bayer Material Science (BMS) announced that it derived an occupational exposure limit (OEL) of 0.05 milligrams per cubic meter (mg/m3) for Baytubes, BMS multi-wall carbon nanotubes. According to BMS, “[t]he latest results of sub-chronic inhalation studies support the conclusion that Baytubes act like poorly soluble particles.” BMS derived the OEL based on previous single and recent repeated inhalation studies. BMS states: “All relevant information are now included in the updated Safety Data Sheet and will further ensure that our customers work safely with our Baytubes.”