---
type: "Bill"
title: "Revise definitions in Clean Indoor Air Act"
description: "Revise definitions in Clean Indoor Air Act"
jurisdiction: "us/states/mt"
legislature: "Montana Legislature"
session: "2025"
identifier: "SB 390"
citation: "Montana SB 390 (2025)"
classification: ["bill"]
subjects: ["Buildings and Building Regulations", "Health"]
status: "enacted"
primary_sponsors: ["Willis Curdy"]
version_count: 31
action_count: 44
vote_count: 10
first_action: "2024-12-15T14:46:07+00:00"
last_action: "2025-05-13T13:36:06+00:00"
source: "openstates"
source_identifier: "ocd-bill/35167c84-a08b-4672-9938-d896558c1fc8"
source_url: "https://bills.legmt.gov/#/laws/bill/2/LC3855?open_tab=sum"
source_hash: "83e8b93a8d01bb55aa82d704971952b634e0c68604c4856915179c025d7e608b"
vintage: "2026-07-01"
source_snapshot: "https://data.openstates.org/daily/2026-07-01/public.pgdump"
retrieved_at: "2026-07-06"
confidence: "reported"
tags: ["legislation", "bill", "us-mt"]
---

# Montana SB 390 (2025) — Revise definitions in Clean Indoor Air Act

## Version chain

The bill's text revisions, in order — the diff chain from filing to enrollment.

1. **LC3855.pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=282829)
2. **SB0390.001.001_Amendments-in-Context_final-full.pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=307046)
3. **SB0390.001.002_Amendments-in-Context_final-full.pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=307602)
4. **SB0390_1(1).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=284974)
5. **SB0390_1(2).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=293514)
6. **SB0390_1(3).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=293697)
7. **SB0390_1(4).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=308620)
8. **SB0390_1(5).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=308621)
9. **SB0390_1(6).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=308622)
10. **SB0390_1(7).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=308623)
11. **SB0390_1.pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=284973)
12. **SB0390_2(1).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=309025)
13. **SB0390_2(2).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=311296)
14. **SB0390_2(3).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=311299)
15. **SB0390_2.pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=308649)
16. **SB0390_X(1).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=311301)
17. **SB0390_X(10).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=320631)
18. **SB0390_X(11).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=322671)
19. **SB0390_X(12).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=322672)
20. **SB0390_X(13).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=322673)
21. **SB0390_X(14).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=324950)
22. **SB0390_X(15).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=326954)
23. **SB0390_X(2).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=311302)
24. **SB0390_X(3).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=312107)
25. **SB0390_X(4).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=312108)
26. **SB0390_X(5).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=312109)
27. **SB0390_X(6).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=312110)
28. **SB0390_X(7).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=312111)
29. **SB0390_X(8).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=312112)
30. **SB0390_X(9).pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=317064)
31. **SB0390_X.pdf** (committee substitute) — [source](https://api.legmt.gov/docs/v1/documents/getContent?documentId=311300)

## Votes

- Do Pass — **34–16** (pass) · upper
- Do Pass — **37–12** (pass) · upper
- to_table — **15–0** (pass) · lower
- do_pass — **10–1** (pass) · upper
- Do Pass — **38–12** (pass) · upper
- Do Concur — **59–39** (pass) · lower
- Do Pass — **31–19** (pass) · upper
- Do Concur — **64–35** (pass) · lower
- be_concurred_in_as_amended — **11–10** (pass) · lower
- to_take_from_the_table — **10–5** (pass) · lower

## Sponsors

- Willis Curdy — primary (person)

## Timeline

The legislative action history — every referral, reading, and vote.

- **2024-12-15T14:46:07+00:00** (LC) Drafter Assigned
- **2024-12-24T23:50:30+00:00** (LC) Draft On Hold
- **2025-02-05T21:03:36+00:00** (LC) Draft Taken Off Hold
- **2025-02-12T16:26:31+00:00** (LC) Draft in Legal Review
- **2025-02-12T22:09:41+00:00** (LC) Draft in Edit
- **2025-02-14T19:58:55+00:00** (LC) Draft in Input/Proofing
- **2025-02-15T23:17:51+00:00** (LC) Draft in Final Drafter Review
- **2025-02-16T15:40:30+00:00** (LC) Draft in Assembly
- **2025-02-17T19:47:28+00:00** (LC) Draft Ready for Delivery
- **2025-02-19T15:20:04+00:00** (LC) Draft Delivered to Requester
- **2025-02-20T19:59:43+00:00** (S) Introduced
- **2025-02-21T20:13:39+00:00** (S) First Reading `reading-1`
- **2025-02-21T20:28:00+00:00** (S) Referred to Committee - (S) Public Health, Welfare and Safety `referral-committee`
- **2025-02-27T21:27:58+00:00** (S) Hearing - (S) Public Health, Welfare and Safety
- **2025-03-01T04:14:01+00:00** (S) Committee Executive Action--Bill Passed - (S) Public Health, Welfare and Safety `committee-passage`
- **2025-03-01T18:25:00+00:00** (S) Committee Report--Bill Passed - (S) Public Health, Welfare and Safety `committee-passage`
- **2025-03-06T11:28:00+00:00** (S) Scheduled for 2nd Reading `reading-2`
- **2025-03-06T15:46:00+00:00** (S) 2nd Reading Passed `reading-2, reading-2`
- **2025-03-06T23:28:00+00:00** (S) Scheduled for 3rd Reading `reading-3`
- **2025-03-07T01:56:00+00:00** (S) 3rd Reading Passed `passage, reading-3`
- **2025-03-07T16:18:23+00:00** (S) Transmitted to House
- **2025-03-17T15:20:12+00:00** (H) Referred to Committee - (H) Human Services `referral-committee`
- **2025-03-17T19:15:00+00:00** (H) First Reading `reading-1`
- **2025-03-19T19:09:12+00:00** (H) Hearing - (H) Human Services
- **2025-03-28T22:11:00+00:00** (H) Tabled in Committee - (H) Human Services `amendment-deferral`
- **2025-04-10T00:20:56+00:00** (H) Taken from Table in Committee - (H) Human Services
- **2025-04-10T00:25:24+00:00** (H) Committee Executive Action--Bill Concurred as Amended - (H) Human Services
- **2025-04-11T14:47:00+00:00** (H) Committee Report--Bill Concurred as Amended - (H) Human Services
- **2025-04-11T16:00:00+00:00** (H) Scheduled for 2nd Reading `reading-2`
- **2025-04-11T20:48:00+00:00** (H) 2nd Reading Concurred `reading-2, reading-2`
- **2025-04-11T21:01:00+00:00** (H) Scheduled for 3rd Reading `reading-3`
- **2025-04-12T00:05:00+00:00** (H) 3rd Reading Concurred `passage, reading-3`
- **2025-04-12T01:02:42+00:00** (H) Returned to Senate with Amendments
- **2025-04-14T20:00:00+00:00** (S) Scheduled for 2nd Reading `reading-2`
- **2025-04-14T20:45:00+00:00** (S) 2nd Reading Concurred `reading-2, reading-2`
- **2025-04-15T19:00:00+00:00** (S) Scheduled for 3rd Reading `reading-3`
- **2025-04-15T22:08:00+00:00** (S) 3rd Reading Passed as Amended by House `passage, passage, reading-3, reading-3`
- **2025-04-15T22:36:13+00:00** (S) Sent to Enrolling
- **2025-04-16T21:35:59+00:00** (S) Returned from Enrolling
- **2025-04-22T23:00:10+00:00** (S) Signed by President `passage`
- **2025-05-01T18:00:14+00:00** (H) Signed by Speaker `passage`
- **2025-05-01T18:36:33+00:00** (S) Transmitted to Governor `executive-receipt`
- **2025-05-09T02:46:00+00:00** (S) Signed by Governor `executive-signature`
- **2025-05-13T13:36:06+00:00** Chapter Number Assigned `became-law`

## Source

OpenStates / OpenCivicData bulk snapshot [2026-07-01](https://data.openstates.org/daily/2026-07-01/public.pgdump); origin `ocd-bill/35167c84-a08b-4672-9938-d896558c1fc8`. Confidence: reported (aggregated from official Montana legislature records).