Official Law Citation: Montana Code Annotated Title 70, Chapter 26 and Title 75 (Environmental Protection). Montana law imposes specific mandatory disclosure requirements for mold, radon, and methamphetamine or fentanyl contamination for commercial properties.

While Montana law assumes commercial parties will conduct due diligence, the state mandates specific disclosures for environmental and health hazards that apply to "inhabitable real property," which includes buildings designed as places of business.

1. The Mold Disclosure (MCA § 70-16-703)

Under MCA § 70-16-703, mold disclosure rules apply to "inhabitable real property." Per MCA § 70-16-702, this definition explicitly includes any building designed as a place of business, including warehouses, office buildings, and industrial sites.

Mandatory Disclosure of Known Mold

Landlords and sellers must disclose the presence of mold if they have actual knowledge of it prior to or upon entry into a contract for purchase, rent, or lease. Furthermore, if the building has been tested for mold, the owner must:

• Advise the tenant or buyer that testing has occurred.
• Provide a copy of the test results, if available.
• Provide evidence of any subsequent mitigation or treatment.

The Standard Warning and Immunity

A landlord or seller may provide a standard written disclosure statement (the "Mold Disclosure" warning) on at least one document executed prior to or contemporaneously with the offer. While providing this specific warning text is optional, doing so—combined with the mandatory disclosure of known mold and test results—grants the owner statutory immunity from civil liability regarding the presence of mold.

2. Radon Disclosure (MCA § 75-3-606)

For the purchase and sale of inhabitable real property, including commercial buildings, a specific radon disclosure statement must be provided on at least one document executed prior to or contemporaneously with the offer. If the seller knows the building has been tested for radon, they must provide the results and evidence of mitigation to the buyer.

3. Methamphetamine and Fentanyl Contamination (MCA § 75-10-1305)

Under MCA § 75-10-1305, an owner of inhabitable property (residential or commercial) who knows the property was used as a clandestine methamphetamine or fentanyl drug lab, or has been contaminated by the consumption (smoke) of methamphetamine or fentanyl, must notify any subsequent occupant or purchaser in writing before a lease or sale agreement is signed.

This disclosure requirement is only lifted once the property has been certified as remediated to Department of Environmental Quality (DEQ) standards and removed from the state's registry of contaminated properties.

4. Asbestos and Environmental Hazards

For older commercial buildings (especially industrial sites and older office buildings), landlords should be aware of federal regulations regarding asbestos. While not a Montana-specific law, the presence of Asbestos-Containing Materials (ACM) must be disclosed to commercial tenants and contractors performing build-outs or renovations.

In complex commercial leases, landlords often require tenants to sign extensive environmental indemnification clauses, protecting the landlord if the tenant's business operations introduce hazardous materials to the site.

See our Commercial Lease RequirementsPreview unavailable guide.

How Landager Helps

Landager tracks lease terms, payment deadlines, and important communications - making it easy to stay compliant with Montana regulations.

Back to Montana Landlord-Tenant Laws OverviewPreview unavailable.