OSHA requirements are set by statute, standards and regulations. Our interpretation letters explain these requirements and how they apply to particular circumstances, but they cannot create additional employer obligations. This letter constitutes OSHA's interpretation of the requirements discussed. Note that our enforcement guidance may be affected by changes to OSHA rules. Also, from time to time we update our guidance in response to new information. To keep apprised of such developments, you can consult OSHA's website at https://www.osha.gov.

February 28, 2011

Mr. Corey Lane

Dear Mr. Lane:

Thank you for your December 12, 2010, letter to the Occupational Safety and Health Administration (OSHA), in which you ask what it means for a hazard to be "first discovered" and also how OSHA calculates an employee's working lifetime. This letter constitutes OSHA's interpretation only of the requirements discussed and may not be applicable to any question not delineated within your original correspondence.

Question 1: The May 4, 2001, interpretation letter addressed to Congressman Joseph Pitts states that "...Congress authorized OSHA to issue penalties, if appropriate, when hazards are first discovered." Please define "first discovered."

Response: You are essentially asking for clarification on the instance from which OSHA's statute of limitations begins to run. In section 9 of the 1970 Occupational Safety and Health Act (the OSH Act), 29 U.S.C. § 658, Congress authorized OSHA to issue citations upon the violation of section 5(a)(l), 29 U.S.C. § 654(a)(1) (general duty clause), any standard, rule or order promulgated pursuant to section 6,29 U.S.C. §655 (Occupational Safety and Health Standards), or any regulation prescribed pursuant to the OSH Act. Section 9 also states that "[n]o citation may be issued... after the expiration of six months following the occurrence of any violation." In other words, in those instances where OSHA will issue citations, it must generally do so within six months from the date the violation occurred. Thus, OSHA must generally issue citations within six months from the date OSHA first discovers the violation during an inspection. Where the actions or omissions of the employer concealed the existence of the violation, however, this six-month period is tolled until such time that OSHA learns or could have learned of the violation.

Question 2: Section 6(b)(5) of the OSH Act, 29 U.S.C. § 655(b)(5), states that OSHA, in promulgating health standards, must "...set the standard which most adequately assures, to the extent feasible, on the basis of the best available evidence, that no employee will suffer material impairment of health or functional capacity even if such employee has regular exposure to the hazard dealt with by such standard for the period of his working life." My understanding is that "working life" is generally considered to be 250 days (five days per week for 50 weeks) per year for 45 years. Please confirm.

Response: For promulgating health standards, the usual hourly, daily, weekly, and yearly components when calculating an employee's "working life" are 8 hours per day, 5 days per week, 48 weeks per year for 45 years.

Since you are located in Washington State, you should also consider contacting the Washington State Department of Labor and Industries (Washington State L&I). Washington State operates its own occupational safety and health program under a plan approved and monitored by Federal OSHA. Under this plan, Washington State L&I promulgates and enforces, under authority of State law, occupational safety and health standards that are at least as effective as those of Federal OSHA, and is obligated to enforce them as effectively as Federal OSHA does. Section 18(c) of the OSH Act, 29 U.S.C. § 667(c). You may contact Washington State L&I at the following address for more information:

Washington State Department of Labor & Industries
Division of Occupational Safety and Health
P.O. Box 44600
Olympia, WA 98504-4600
Tel. no. 1-800-423-7233, or 1-360-902-4805;
Fax no. 360-902-5798; TDD 360-902-5797

Thank you for your interest in occupational safety and health. We hope you find this information helpful. Please be aware that OSHA's enforcement guidance is subject to periodic review and clarification, amplification, or correction. Such guidance could also be affected by subsequent rulemaking. In the future, should you wish to verify that the guidance provided herein remains current, you may consult OSHA's website at www.osha.gov. If you have any further questions, please feel free to contact the Office of General Industry Enforcement at (202) 693-1850.


Thomas Galassi, Director
Directorate of Enforcement Programs

cc: OSHA Region X

[Corrected on 09/28/2012]