The MSDS for a material provides guidance for its toxicity, and is sometimes summarized in the NFPA triangle. Any material tagged as a hazard level of 1 or greater (4 is the maximum) most likely should be handled as hazardous.
Massachusetts regulates waste petroleum oils as hazardous waste (motor, hydraulic, vacuum pump oils, cutting oils)
Effectively all non-polar solvents are hazmats, e.g. petroleum distillates, kerosene, de-greasing solvents, acetone, hexanes, turpentine etc.
Exceptionally hazardous
Isopropanol and methanol are hazardous.
Etching solutions:
These are hazardous waste on two grounds:
Acids with pH below / above 5.5 - 10.5 may not be disposed of down drains.
Arsenic, Barium, Cadmium, Chromium, Lead, Mercury, Selenium, and Silver are regulated as hazardous wastes.
MWRA also regulates zinc and copper in wastewater discharges at > 1 mg/liter.
Hazardous corrosives include essentially all strong acids e.g. hydrochloric acid, sulphuric acid, ferric chloride … etc.
SLA printing resins (primarily acrylic monomers) rate an NFPA ‘1’ for both flammability, and toxicity. The main reason to avoid exposure is because when sensitized to these materials, dental adhesives become acutely toxic.