1,3-Butadiene
For 1,3-Butadiene, cfr section is 1910.1051; action level is 0.5 ppm calculated as an eight (8)-hour time-weighted average; pel is one (1) part BD per million parts of air (ppm) measured as an eight (8)-hour time-weighted average; surveillance trigger is each employee with exposure to BD at concentrations at or above the action level on 30 or more days or for employees who have or may have exposure to BD at or above the PELs on 10 or more days a year; exam frequency is Every 3 years after the initial physical examination, verified against its source on 2026-09-17.
- Substance
- 1,3-Butadiene
- CFR section
- 1910.1051
- Action level
- 0.5 ppm calculated as an eight (8)-hour time-weighted average verified
- PEL
- one (1) part BD per million parts of air (ppm) measured as an eight (8)-hour time-weighted average verified
- Surveillance trigger
- each employee with exposure to BD at concentrations at or above the action level on 30 or more days or for employees who have or may have exposure to BD at or above the PELs on 10 or more days a year verified
- Exam frequency
- Every 3 years after the initial physical examination verified
- Record retention
- Medical screening and surveillance records shall be maintained for each employee for the duration of employment plus 30 years verified
What the source says
(k) Medical screening and surveillance—(1) Employees covered. The employer shall institute a medical screening and surveillance program as specified in this paragraph for: (i) Each employee with exposure to BD at concentrations at or above the action level on 30 or more days or for employees who have or may have exposure to BD at or above the PELs on 10 or more days a year;
— law.cornell.edu, retrieved 2026-08-12
Where each value comes from
This source states these in separate places, so each value is shown with the passage that states it.
Action level
(b) Definitions: For the purpose of this section, the following definitions shall apply: Action level means a concentration of airborne BD of 0.5 ppm calculated as an eight (8)-hour time-weighted average.
PEL
This section means this 1,3-butadiene standard . (c) Permissible exposure limits (PELs)—(1) Time-weighted average (TWA) limit. The employer shall ensure that no employee is exposed to an airborne concentration of BD in excess of one (1) part BD per million parts of air (ppm) measured as an eight (8)-hour time-weighted average.
Exam frequency
(A) An initial physical examination that meets the requirements of this rule, if twelve months or more have elapsed since the last physical examination conducted as part of a medical screening program for BD exposure; (B) Before assumption of duties by the employee in a job with BD exposure; (C) Every 3 years after the initial physical examination;
Record retention
(A) The name of the employee; (B) Physician's or other licensed health care professional 's written opinions as described in paragraph (k)(7) of this section; (C) A copy of the information provided to the physician or other licensed health care professional as required by paragraphs (k)(7)(ii)-(iv) of this section. (iii) Medical screening and surveillance records shall be maintained for each employee for the duration of employment plus 30 years, in accordance with 29 CFR 1910.1020 .
— all from law.cornell.edu, retrieved 2026-08-12
Source
- law.cornell.eduhttps://www.law.cornell.edu/cfr/text/29/1910.1051