1910.106(b)(2)(ii): Spacing (shell-to-shell) between aboveground tanks
Key takeaways
- 1910.106(b)(2)(ii) is part of OSHA's general industry standards (29 CFR Part 1910, Subpart H).
- OSHA cited it 5 times in the last 3 years, in 5 inspections, with $6,826 in current penalties.
- Related part: 1910.106(b) Tank storage (99 citations).
- Free 5-minute toolbox talk for your crew below.
In this article
What this rule covers
29 CFR 1910.106(b)(2)(ii) ("Spacing (shell-to-shell) between aboveground tanks") is one requirement inside 1910.106 Flammable liquids, an OSHA general industry standard (Part 1910, Subpart H). The official text below is copied word for word from the Electronic Code of Federal Regulations (eCFR). The numbers, injury cases and training on this page show how OSHA enforces it on real job sites.
Official text
(ii) Spacing (shell-to-shell) between aboveground tanks. 5 citations
(a) The distance between any two flammable liquid storage tanks shall not be less than 3 feet.
(b) Except as provided in paragraph (b)(2)(ii)(c) of this section, the distance between any two adjacent tanks shall not be less than one-sixth the sum of their diameters. When the diameter of one tank is less than one-half the diameter of the adjacent tank, the distance between the two tanks shall not be less than one-half the diameter of the smaller tank.
(c) Where crude petroleum in conjunction with production facilities are located in noncongested areas and have capacities not exceeding 126,000 gallons (3,000 barrels), the distance between such tanks shall not be less than 3 feet.
(d) Where unstable flammable liquids are stored, the distance between such tanks shall not be less than one-half the sum of their diameters.
(e) When tanks are compacted in three or more rows or in an irregular pattern, greater spacing or other means shall be provided so that inside tanks are accessible for firefighting purposes.
(f) The minimum separation between a liquefied petroleum gas container and a flammable liquid storage tank shall be 20 feet, except in the case of flammable liquid tanks operating at pressures exceeding 2.5 p.s.i.g. or equipped with emergency venting which will permit pressures to exceed 2.5 p.s.i.g. in which case the provisions of subdivisions (a) and (b) of this subdivision shall apply. Suitable means shall be taken to prevent the accumulation of flammable liquids under adjacent liquefied petroleum gas containers such as by diversion curbs or grading. When flammable liquid storage tanks are within a diked area, the liquefied petroleum gas containers shall be outside the diked area and at least 10 feet away from the centerline of the wall of the diked area. The foregoing provisions shall not apply when liquefied petroleum gas containers of 125 gallons or less capacity are installed adjacent to fuel oil supply tanks of 550 gallons or less capacity.
Source: eCFR, text current as of 2026-10-15. Read all of 1910.106.
Where and how often it was cited
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Related parts of this rule
- 1910.106(b) Tank storage 99 citations
- 1910.106(b)(6) Sources of ignition 59 citations
- 1910.106(b)(2) Installation of outside aboveground tanks 23 citations
- 1910.106(b)(2)(vii) Drainage, dikes, and walls for aboveground tanks— 13 citations
- 1910.106(b)(4) Installation of tanks inside of buildings 6 citations
- 1910.106(b)(5) Supports, foundations, and anchorage for all tank locations 5 citations
- 1910.106(b)(1) Design and construction of tanks 4 citations
- 1910.106(b)(4)(ii) Vents 2 citations
- 1910.106(b)(4)(iv) Tank openings other than vents 2 citations
- 1910.106(b)(7) Testing 2 citations
- 1910.106(b)(1)(i) Materials 1 citations
- 1910.106(b)(5)(ii) Fire resistance
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Sources
- 29 CFR 1910.106 (eCFR), text current as of 2026-10-15
- U.S. Department of Labor enforcement data: OSHA inspections, citations and accident records, copied nightly; data as of 2026-10-21
3-year window. Federal OSHA only; state-plan rules are not counted. Plain-language text is a summary, not legal advice; the official text controls. Black Belt Safety is not part of OSHA or the Department of Labor.