This information is provided free of charge by the Department of Industrial Relations
from its web site at www.dir.ca.gov. These regulations are for the
convenience of the user and no representation or warranty is made that the information
is current or accurate. See full disclaimer at https://www.dir.ca.gov/od_pub/disclaimer.html.
Subchapter 7. General Industry Safety Orders
Group 16. Control of Hazardous Substances
Article 107. Dusts, Fumes, Mists, Vapors and Gases
(1) This section establishes requirements for controlling employee exposure to airborne contaminants and skin contact with those substances which are readily absorbed through the skin and are designated by the “S” notation in Table AC-1 at all places of employment in the state.
(2) When this section references another section for controlling employee exposures to a particular airborne contaminant, the provisions of this section for such substance shall apply only to those places of employment which are exempt from the other standard.
Exception: The provisions for strontium chromate contained in this section shall continue to apply in all workplaces and shall be in addition to the requirements stated in Sections 1532.2, 5206, and 8359.The provisions for strontium chromate contained in this section shall continue to apply in all workplaces and shall be in addition to the requirements stated in Sections 1532.2, 5206, and 8359.
Note: Table AC-1 of this section presents concentration limits for airborne contaminants to which nearly all workers may be exposed daily during a 40-hour workweek for a working lifetime without adverse effect. Because of some variation in individual susceptibility, an occasional worker may suffer discomfort, aggravation of a pre-existing condition, or occupational disease upon exposure to concentrations even below the values specified in these tables. The exposure limits established by this section reflect current medical opinion and industrial hygiene practice, doubts being resolved on the side of safety, and are intended to be used in accordance with good industrial hygiene practice by qualified persons. The division recognizes the need for almost continuous review of these concentration limits and also anticipates the need for including new or additional substances. Harmful exposure to any substances not listed in this section shall be controlled in accordance with section 5141.
Ceiling Limit. The maximum concentration of an airborne contaminant to which an employee may be exposed at any time.
Eight-Hour Time-Weighted Average Concentration (TWA). An employee's exposure, as measured or calculated by the formula in Appendix A, to an airborne contaminant during a workday.
Permissible Exposure Limit (PEL). The maximum permitted 8-hour time-weighted average concentration of an airborne contaminant.
Short Term Exposure Limit (STEL). A 15-minute time-weighted average exposure which is not to be exceeded at any time during a workday even if the 8-hour time-weighted average is below the PEL. An averaging period other than 15 minutes may be specified in the footnotes at the end of Table AC-1.
(c) Exposure Limits.
(1) Permissible Exposure Limits (PELs).
(A) An employee exposure to an airborne contaminant in a workday, expressed as an 8-hour TWA concentration, shall not exceed the PEL specified for the substance in Table AC-1.
(B) When substances have additive health effects as described in section (B) of the Appendix to section 5155, the value of D shall not exceed unity.
(2) Short Term Limits.
(A) Short Term Exposure Limit. An employee exposure to an airborne contaminant, expressed as a 15-minute time-weighted average concentration, shall not exceed the STEL specified for the substance in Table AC-1 at any time during the workday. If another averaging period is indicated in the footnotes to Table AC-1, the time-weighted average exposure over that time period shall not exceed the specified STEL at any time during the workday.
(B) All Other Substances Without a Ceiling Limit. Employee exposure to concentrations above the PEL shall be controlled so as to prevent harmful effects such as narcosis, significant irritation of the eyes, skin or respiratory tract, or chronic or irreversible tissue change.
Note: Such substances are not known to cause adverse effects if the maximum concentration of exposure is limited in accordance with the following guidelines.
(From Table AC-1)
For Maximum Concentration
0 to 1
>1 to 10
*Use ppm value unless the concentration is only expressed in mg/M3
(3) Ceiling Limits. Employee exposures shall be controlled such that the applicable ceiling limit specified in Table AC-1 for any airborne contaminant is not exceeded at any time.
(d) Skin Notation and Protective Clothing. The substances designated by “S” in the skin notation column of Table AC-1 may be absorbed into the bloodstream through the skin, the mucous membranes and/or the eye, and contribute to the overall exposure. Appropriate protective clothing shall be provided for and used by employees as necessary to prevent skin absorption.
Note: The above requirement does not remove the employer's responsibility to provide appropriate protection from corrosive or skin irritating materials which may not bear the “S” designation.
(e) Workplace Monitoring.
(1) Whenever it is reasonable to suspect that employees may be exposed to concentrations of airborne contaminants in excess of levels permitted in section 5155(c), the employer shall monitor (or cause to have monitored) the work environment so that exposures to employees can be measured or calculated.
(2) When exposures to airborne contaminants are found or are expected to exceed allowable levels, measures to control such harmful exposures shall be instituted in accordance with section 5141.
(3) For the adequate protection of employees, the person supervising, directing or evaluating the monitoring and control methods shall be versed in this standard and shall be competent in industrial hygiene practice.
Note: To facilitate the detection of conditions leading to serious overexposures, the screening of the work environment by any person authorized by the employer, using appropriate measuring devices, is encouraged.
(4) All monitoring results shall be recorded and such records shall be retained in accordance with section 3204.
(f) Medical Surveillance. A medical surveillance program approved by the division may be required to ensure satisfactory maintenance of employee health and to ascertain the effectiveness of the control method(s).
Appendix to Section 5155
(A) Computation for Exposures to Contaminants with Independent Health Effects.
The 8-hour time-weighted average concentration (TWA) of a single substance to which an individual is exposed during a workday shall be calculated using the following formula to determine compliance with the PEL specified in Table AC-1.
where T is the duration in hours of the exposure to a substance at the concentration C. For multiple substances with independent health effects, an independent comparison of each TWA with the corresponding PEL shall be made to determine compliance.
*Note: Eight (8) is used as denominator regardless of total hours of workday.
EXAMPLE: To illustrate the use of this formula, assume Substance A has an 8-hour time weighted average permissible exposure limit of 100 ppm noted in Table AC-1 and an employee is exposed to an airborne concentration of Substance A of 150 ppm for 2 hours, 75 ppm for 3 hours, and 50 ppm for 4 hours during a 9-hour workday:
TWA = [(150 x 2) + (75 x 3) + (50 x 4)]/8* = 91 ppm.
The series of exposures in this example are equivalent to an 8-hour exposure at a concentration of 91 ppm which is below the PEL value of 100 ppm specified for Substance A.
(B) Computation for Exposures to Contaminants with Additive Health Effects.
In the absence of information to the contrary, the adverse health effects of exposure to two or more toxic materials during the workday shall be considered additive and the following formula shall be used for calculating D, the fraction of the allowable daily exposure.
where TWA is the time-weighted average concentration of a particular substances involved in the exposure (as calculated by the formula in Section (A) of this Appendix), and PEL is the corresponding permissible exposure limit for that substance as specified by Table AC-1. The value of D shall not exceed unity.
Example: To illustrate the use of this formula, consider the following exposures:
Since D is less than unity (1), the exposure to multiple contaminants is within acceptable limits.
Health effects for multiple contaminants are not considered additive when different organs of the body are affected by individual substances, or where the same effect (such as narcosis) is produced by two substances but the PEL for one substance is based on another effect. For example, vinyl chloride and toluene can both cause narcotic effects, however, the PEL for vinyl chloride is established to protect against cancer while the PEL for toluene is established to protect against non-carcinogenic effects.
PERMISSIBLE EXPOSURE LIMITS FOR CHEMICAL CONTAMINANTS
Footnotes to Table AC-1
(a) The Chemical Abstracts Service Registry Number is a designation used to identify a specific compound or substance regardless of the naming system; these numbers were obtained from the Desk Top Analysis Tool for the Common Data Base and from the Chemical Abstracts Indexes.
(b) Refer to section 5155(d) for the significance of the Skin notation.
(c) Trade Names Removed from Table AC-1.
Phenylether and Biphenyl
(d) For the definition and the application of the Permissible Exposure Limit (PEL), refer to section 5155(b) and (c)(1).
(e) Parts of gas or vapor per million parts of air by volume at 25oC and 760mm Hg pressure.
(f) Milligrams of substance per cubic meter of air at 25oC and 760mm Hg pressure.
(g) Refer to section 5155(b) and (c)(3) for the significance of the Ceiling notation. A “C” notation in this column means the values given in the PEL columns are ceiling values. A numerical entry in this column represents a ceiling value in addition to the TWA values.
(h) A number of gases and vapors, when present in high concentrations, act primarily as asphyxiants without other adverse effects. A concentration limit is not included for each material because the limiting factor is the available oxygen. (Several of these materials present fire or explosion hazards.)
(i) Coal tar pitch volatiles (benzene or cyclohexane-soluble fraction) include fused polycyclic hydrocarbons (some of which are known carcinogens) which volatilize from the distillation residues of coal, petroleum (excluding asphalt), wood, and other organic matter. Asphalt (CAS 8052-42-4, and CAS 64742-93-4) is not covered under the “coal tar pitch volatiles” standard.
(j) This standard applies to the cotton waste processing operations of waste recycling (sorting, blending, cleaning, and willowing) and garnetting. It does not apply to cotton gins, cottonseed oil industry, or operations covered by section 5190.
(k) A PEL of 0.05 ppm shall apply to exposures involving a mixture of ethylene glycol dinitrate and nitroglycerin.
(l) As sampled by method that does not collect vapor.
(m) Thermal decomposition of the fluorocarbon chain in air leads to the formation of oxidized products containing carbon, fluorine and oxygen. An index of exposure to these products is possible through their alkaline hydrolysis followed by a quantitative determination of fluoride content. No particular concentration limit is specified pending evaluation of the toxicity of the products but concentrations should be kept below the sensitivity of the analytical method.
(n) The concentration and percentage of the particulate used for this limit are determined from the fraction passing a size selector with the following characteristics:
(unit density sphere)
(o) Refer to sections 5155(b) and (c)(2) for the definition and application of the Short Term Exposure Limit (STEL).
(q) Fibers per cubic centimeter of air at 25oC and 760mm Hg pressure. To be considered a fiber for this limit, the particle must be longer than 5mm, have a length to diameter ratio of three or more, and have a diameter less than 3mm. The National Institute for Occupational Safety and Health (NIOSH), Method 7400, Issue 2, August 15, 1994, which is hereby incorporated by reference, shall be used for measuring airborne fiber concentrations.
(r) Compliance with the subtilisins PEL is assessed by sampling with a high volume sampler (600-800 liters per minute) for at least 60 minutes.
(s) The concentration and percentage of the particulate used for this limit are determined from the fraction passing a size selector with the following characteristics:
(unit density sphere)
(t) Glutaraldehyde can cause occupational asthma and skin sensitization responses such as contact dermatitis. Exposure related symptoms may include one or more of the following: shortness of breath, chest tightness, wheeze, cough, skin rash, hives, and irritation of the nose, throat, skin or eye. Hazard communication training required by sections 5191 or 5194 shall address these health hazards and symptoms along with the measures taken by the employer to evaluate and control exposures that can include medical evaluations, exposure monitoring, ventilation systems, work practices, and personal protective equipment. The communication system required by section 3203 shall inform employees where to report possible health symptoms and where to ask questions, report concerns, and receive information about the employer's evaluation and control measures.
(u) This PEL applies to the sum of the exposures to the substance in the vapor state and from the particulate fraction specified in footnote (s) in this table.
31. Editorial correction of Table AC-1, entries for styrene, sulfometuron methyl and 4-vinyl cyclohexene (Register 2001, No. 24).
32. Change without regulatory effect amending Table AC-1 entry for dicyclohexylmethane-4,4i-diisocyanate filed 7-19-2001 pursuant to section 100, title 1, California Code of Regulations (Register 2001, No. 29).
33. Editorial correction of Table AC-1, entries for aluminum alkyls, 4,4'-diaminobiphenyl, 2,6-Di-tert-butyl-p-cresol, rubber solvent, TEPP and tetramethyl thiuram disulfide (Register 2001, No. 49).
34. Change without regulatory effect amending appendix and Table AC-1 filed 1-17-2002 pursuant to section 100, title 1, California Code of Regulations (Register 2002, No. 3).
36. Amendment of Table AC-1, including new footnote (s), filed 10-4-2004; operative 11-3-2004 (Register 2004, No. 41).
37. Amendment of Table AC-1, including new footnotes (t) and (u), filed 6-6-2006; operative 7-6-2006. (The ceiling limit of 0.05 ppm for Glutaraldehyde will take effect 7-6-2008) (Register 2006, No. 23).
38. Editorial correction of Table AC-1, Beryllium and Methyl 2-cyanoacrylate (Register 2006, No. 29).
39. Amendment of subsection (a)(2) and amendment of Table AC-1 filed 9-19-2006; operative 9-19-2006. Submitted to OAL for printing only pursuant to Labor Code section 142.3(a)(3) (Register 2006, No. 38).
47. Editorial correction of Table AC-1 (Register 2012, No. 37).
48. Amendment of Table AC-1, entry for ethylbenzene, filed 8-27-2013; operative 10-1-2013 (Register 2013, No. 35).
49. Editorial correction of Table AC-1 entry for 1,2-Dibromoethane (Register 2013, No. 50).
50. Amendment of Table AC-1 adding new entry for N-Methylpyrrolidone filed 1-7-2014; operative 4-1-2014 (Register 2014, No. 2).
51. Amendment of Table AC-1 entry for naphthalene filed 6-24-2014; operative 10-1-2014 (Register 2014, No. 26).
52. Amendment of Table AC-1 entry for hydrogen chloride filed 11-26-2014; operative 1-1-2015 (Register 2014, No. 48).
53. Amendment of Table AC-1 filed 10-17-2016; operative 10-17-2016. Submitted to OAL for filing and printing only pursuant to Labor Code section 142.3(a)(3) (Register 2016, No. 43).
54. Editorial correction of Table AC-1 (Register 2017, No. 12).
55. Amendment of Table AC-1 (entries for Wood dust and Wood dust, Western red cedar) filed 4-4-2017; operative 7-1-2017 (Register 2017, No. 14).
56. Amendment of Table AC-1 (entry for beryllium) filed 10-2-2017; operative 10-2-2017 pursuant to Labor Code section 142.3. Submitted to OAL for filing and printing only pursuant to Labor Code section 142.3(a)(4) (Register 2017, No. 40).
57. Amendment of Table AC-1 (entry for benzyl chloride) filed 12-5-2017; operative 4-1-2018 (Register 2017, No. 49).