Archive Notice - OSHA Archive

NOTICE: This is an OSHA Archive Document, and may no longer represent OSHA Policy. It is presented here as historical content, for research and review purposes only.

Department of Labor Logo
OSHA Trade Release

Please note: As of January 20, 2021, information in some news releases may be out of date or not reflect current policies.
Trade News Release
June 11, 2007
Contact: Office of Communications
Phone: (202) 693-1999

OSHA defines "on site in one location" for Process Safety Management of Highly Hazardous Chemicals standard

WASHINGTON -- The U.S. Department of Labor's Occupational Safety and Health Administration (OSHA) has issued its official interpretation and explanation of the phrase "on site in one location" in the "Application" section of OSHA's Process Safety Management (PSM) of Highly Hazardous Chemicals standard. The interpretation was published in the June 7 Federal Register.

"This official interpretation should help provide additional clarity to an earlier Notice of Proposed Rulemaking on the threshold quantities of highly hazardous chemicals," said Assistant Secretary of Labor for OSHA Edwin G. Foulke, Jr. "This interpretation has been accepted by our stakeholders and should further aid those who are affected by the PSM standard."

OSHA interprets "on site in one location" to mean that the standard applies when a threshold quantity of a highly hazardous chemical (HHC) exists within an area under the control of an employer or group of affiliated employers. It also applies to any group of vessels that are interconnected, or in separate vessels that are close enough in proximity that the HHC could be involved in a potential catastrophic release.

The meaning of "on site in one location" was at issue in a recent case before the Occupational Safety and Health Review Commission. In that decision, the Review Commission asked whether that language was meant to limit, in some way, the applicability of the standard to a highly-hazardous chemical process. The Review Commission decided it could not determine whether the cited activities were both "on site" and "in one location," and requested that OSHA clarify its interpretation.

Under the Occupational Safety and Health Act of 1970, employers are responsible for providing a safe and healthful workplace for their employees. OSHA's role is to assure the safety and health of America's working men and women by setting and enforcing standards; providing training, outreach, and education; establishing partnerships; and encouraging continual process improvement in workplace safety and health. For more information, visit


U.S. Labor Department news releases are accessible on the Internet at The information in this news release will be made available in alternate format upon request (large print, Braille, audio tape or disc) from the COAST office. Please specify which news release when placing your request at (202) 693-7765 or TTY (202) 693-7755. The U.S. Department of Labor is committed to providing America's employers and employees with easy access to understandable information on how to comply with its laws and regulations. For more information, please visit