Q.01

What did EPA's draft risk evaluation find for 1,2-dichloropropane?

EPA's draft risk evaluation for 1,2-dichloropropane (CASRN 78-87-5) preliminarily found that it presents unreasonable risk to human health. Of the 15 conditions of use assessed, 14 significantly contribute to that risk; the exception is distribution in commerce. EPA found no unreasonable risk to the general population, including fenceline communities, or to the environment.

Approach: The TSCA risk evaluation register in our datasets holds no 1,2-dichloropropane documents, so this comes from EPA's own pages. I used EPA's announcement and the executive summary of the August 2026 public release draft (EPA-740-D-26-035).

Release and status

  • EPA released the draft on September 2, 2026. Public comment runs for 60 days after the notice appears in the Federal Register, under docket EPA-HQ-OPPT-2018-0428 (EPA announcement).
  • The draft hazard assessment went through peer review by EPA's Science Advisory Committee on Chemicals (SACC) in August 2026. Background: EPA named the chemical a high-priority substance in December 2019 and issued the final scope in August 2020 (draft, p. 11).

Hazard basis (draft, p. 13)

  • Non-cancer effects: central nervous system depression, and blood effects (more reticulocytes, or immature red blood cells) after medium-term and long-term oral exposure.
  • Oral cancer: the cancer slope factor is based on liver tumours in mice in the 1986 NTP two-year study. Bile duct tumours in Japanese print-shop workers support it.
  • Inhalation cancer: the inhalation unit risk is based on nasal tumours in male rats (Umeda et al., 2010).
  • Dermal route: no dermal studies were suitable. Dermal risk was estimated from the oral values.

Workers and bystander workers (draft, pp. 11, 13-14)

  • 12 conditions of use were assessed for workers. 11 contribute to unreasonable risk, mainly through inhalation; 8 also contribute through skin contact.
  • 4 also contribute to risk for "occupational non-users", meaning nearby workers who don't handle the chemical.
  • The 11 are:
    • domestic manufacture
    • import
    • processing as a reactant
    • incorporation into a formulation
    • repackaging
    • industrial use as a processing aid
    • commercial laboratory chemical
    • three commercial cleaning and furnishing care products: all-purpose liquid spray cleaner, all-purpose waxes and polishes, and all-purpose liquid cleaner and polish
    • disposal
  • The 4 that also cover nearby workers are the three commercial cleaning products and disposal.

Consumers and bystanders (draft, pp. 11-12, 14)

  • All three consumer uses of these stone cleaning products contribute to unreasonable risk, mostly from short-term inhalation.
  • The spray cleaner also carries long-term non-cancer and cancer risk by inhalation and skin contact.
  • EPA notes that its test-order data show current US stone cleaning products no longer contain 1,2-dichloropropane. It still treats consumer use as "reasonably foreseen" for three reasons:
    • the products were reformulated only a few years ago;
    • products containing it are sold outside the US;
    • older products may still be in use.
  • EPA says it is uncertain whether this use is plausible in the US and asks for comment on it.

General population and environment (draft, pp. 14-15)

  • No condition of use contributes to unreasonable risk from outdoor air, drinking water, swimming or eating fish.
  • No condition of use contributes to unreasonable risk to aquatic, sediment, soil or land organisms.

Next steps: EPA will finalise the evaluation after weighing public and SACC comments. If the final evaluation still finds unreasonable risk, EPA will propose risk management rules under TSCA section 6(a) (EPA announcement).

Q.02

When is the comment deadline?

Comments on EPA's draft risk evaluation for 1,2-dichloropropane are due November 3, 2026. The Federal Register notice says: "Comments must be received on or before November 3, 2026." That is 10 days from today.

Approach: The TSCA risk evaluation register in our datasets holds no 1,2-dichloropropane documents, so I took the date from the Federal Register record for the notice and EPA's signed pre-publication copy.

  • Notice: "1,2-Dichloropropane Draft Risk Evaluation Under the Toxic Substances Control Act (TSCA); Notice of Availability and Request for Comment." It is Federal Register document 2026-18117, published September 4, 2026 at 91 FR 56882 (Federal Register record).
  • Where to comment: docket EPA-HQ-OPPT-2018-0428 on regulations.gov. The notice's FRL number is 13553-01-OCSPP (Federal Register record; EPA pre-publication copy, p. 1).
  • How the date is set: EPA said it would take comments for 60 days after the notice was published (EPA announcement). Sixty days from September 4 is November 3. The Federal Register record shows no extension.
Q.03

What about trans-1,2-dichloroethylene?

Comments on EPA's draft risk evaluation for trans-1,2-dichloroethylene (CASRN 156-60-5) are due October 26, 2026, two days from today. The Federal Register notice says: "Comments must be received on or before October 26, 2026." On the substance, EPA preliminarily found unreasonable risk to human health. Of the 25 conditions of use assessed, 20 significantly contribute to that risk, mostly through workers breathing it in. EPA found no unreasonable risk to the general population or the environment [1].

Approach: I read the August 2026 public release draft in the TSCA risk evaluation register, and the Federal Register notice of availability for the deadline. A Federal Register search for 2026 notices on this chemical found no extension notice.

Notice and comment logistics (Federal Register notice, 91 FR 55337-55338)

  • FR Doc. 2026-17478, published August 27, 2026; FRL-13477-01-OCSPP.
  • Docket EPA-HQ-OPPT-2018-0465 on regulations.gov. Don't submit confidential business information (CBI) through regulations.gov or by email; follow EPA's CBI instructions.
  • Technical contact: Daniel Whitby (OPPT), trans-1.2-Dichloroethylene.TSCA@epa.gov.
  • Background: EPA designated it high-priority in December 2019 (84 FR 71924) [2] and issued the final scope on September 4, 2020.

Hazard basis [3]

  • Short-term inhalation: sensory irritation and acute neurotoxicity.
  • Medium- and long-term exposure: immune effects, by the oral, dermal and inhalation routes.
  • Short-term skin or oral contact: no acute non-cancer hazard identified.
  • Cancer: EPA preliminarily concluded that a quantitative cancer risk assessment is not warranted. This differs from 1,2-dichloropropane, where cancer values drove part of the risk.

Workers and nearby workers (ONUs) [3][4]

  • 19 conditions of use contribute to inhalation risk for workers. For 13 of them, the risk also extends to occupational non-users (ONUs), meaning nearby workers who don't handle the chemical.
  • EPA found no unreasonable risk from skin contact for workers.
  • The 19 are:
    • Manufacturing: domestic manufacture; import
    • Processing:
      • as a reactant (intermediate)
      • incorporation into formulations as a solvent
      • solvent purification for semiconductor manufacturing
      • incorporation into articles
      • repackaging
      • recycling
    • Industrial/commercial cleaning: vapor degreasing; aerosol spray cleaner/degreaser; non-aerosol cleaner/degreaser
    • Other industrial/commercial uses:
      • mold release
      • urethane coatings
      • lubricants and greases
      • solvent-based adhesives, sealants and adhesive accelerants
      • smoothing fluid in additive manufacturing
      • refrigerants
      • specialized detection indicator materials
      • blowing agent in polymer foam

Consumers [4][5]

  • Consumer cleaner/degreaser use (aerosol and non-aerosol) contributes through short- and medium-term inhalation.
  • Bystanders are not at risk, and neither is consumer use as a blowing agent in polymer foam.

Five conditions of use that do not contribute [4]

  • semiconductor and photovoltaic etching and cleaning agents
  • laboratory chemical
  • distribution in commerce
  • disposal
  • consumer polymer foam blowing agent

General population and environment [4][6]

  • No condition of use contributes to unreasonable risk to the general population, including fenceline communities. EPA looked at ambient air, swimming, drinking water and landfill-affected groundwater.
  • No condition of use contributes to risk for aquatic or land organisms. For environmental hazard thresholds, EPA partly relied on trichloroethylene data as a stand-in chemical.

What EPA wants from commenters [7]

  • Exposure controls, PPE and task frequency in the workplace, especially for blowing-agent use.
  • How many facilities do vapor degreasing.
  • Monitoring data for manufacture as a byproduct.
  • How often batch manufacturing runs.
  • PPE use for the two solvent formulation and purification uses.

The SACC peer review of the draft hazard assessment took place August 3-7, 2026. If the final evaluation confirms unreasonable risk, EPA will start rulemaking under TSCA section 6(a) [7].

Q.04