Subchapter 7. General Industry Safety Orders
Group 16. Control of Hazardous Substances
Article 107. Dusts, Fumes, Mists, Vapors and Gases

§5155. Airborne Contaminants, 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.

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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.

a1 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 [FNa1] = 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.

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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:

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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.

Table AC-1
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.

Trade Name Chemical/Generic Name
Abate see Temephos
Ammate see Ammonium Sulfamate
Aqualin see Acrolein
Arasan see Thiram
Azodrin see Moncrotophos
Baygon see Propoxur
Bidrin see Dicrotophos
Butyl Cellosolve see 2-Butoxyethanol
Cellosolve see 2-Ethoxyethanol
Cellosolve Acetate see 2-Ethoxyethyl acetate
Compound 1080 see Sodium Fluoracetate
Coyden see Clopidol
Crag Herbicide see Sesone
Cythion see Malathion
Dasanit see Fensulfothion
Delnav see Dioxathion
Dibrom see Naled
Difolatan see Captafol
Disyston see Disulfoton
Dowtherm A see Phenylether and Biphenyl
Dursban see Chloropyrifos
Dyfonate see Fonofos
Fermate see Ferbam
Freons see Fluorocarbons
Furadan see Carbofuran
Guthion see Azinphos Methyl
Korlan see Ronnel
Lannate see Methomyl
Mariate see Methoxychlor
MLT see Malathion
Moxie see Methoxychlor
Nialate see Ethion
Nankor see Ronnel
Phosdrin see Mevinphos
Pival see Pindone
Plictran see Cyhexatin
Santobrite see Pentachlorophenol
Sevin see Carbaryl
Systox see Demeton
Teflon see Polytetrafluoroethylene
Thimet see Phorate
Thiodan see Endosulfan
Tordon see Picloram
Trolene see Ronnel
Vapona see Dichlorvos
Weedone 638 see 2, 4-D
Zoalene see Dinitolmide

(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 25 o C and 760mm Hg pressure.

(f) Milligrams of substance per cubic meter of air at 25 o C 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 involying 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:

Aerodynamic Diameter
in Micrometers Percent
(unit density sphere) Passing Selector
< 2................ 90
2.5................. 75
3.5................. 50
5.0................. 25
10.................. 0

Source: American Conference of Governmental Industrial Hygienists TLI Committee 1968 Proceedings.

(o) Refer to sections 5155(b) and (c)(2) for the definition and application of the Short Term Exposure Limit (STEL).

(p) (Reserved)

(q) Fibers per cubic centimeter of air at 25o C and 760mm Hg pressure. To be considered a fiber for this limit the glass 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:

Aerodynamic Diameter
in Micrometers Percent
(unit density sphere) Passing Selector
0.................... 100
1.................... 97
2.................... 94
5.................... 87
10................... 77
20................... 65
30................... 58
40................... 54.5
50................... 52.2
100.................. 50

(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) The Ceiling Limit of 0.05 ppm will take effect July 6, 2008. Until that time the following exposure limits will be in effect: PEL 0.05 ppm (8-hour time-weighted average) Ceiling Limit 0.2 ppm.

Note: Authority cited: Section 142.3, Labor Code. Reference: Sections 142.3 and 144.6, Labor Code.

HISTORY

1. Editorial correction of printing errors (Register 84, No. 4). For prior
history, see Register 83, No. 45.

2. Amendment of Table AC-1 filed 3-8-84; effective thirtieth day thereafter
(Register 84, No. 10).

3. Amendment of Tables AC-2 and AC-3 filed 8-30-84; effective thirtieth day
thereafter (Register 84, No. 35).

4. Amendment of Table AC-2 filed 9-26-84; effective thirtieth day thereafter
(Register 84, No. 39).

5. Amendment of Table AC-3 filed 12-13-84; effective thirtieth day thereafter
(Register 84, No. 50).

6. Amendment of Table AC-1 filed 1-16-85; effective thirtieth day thereafter
(Register 85, No. 3).

7. Editorial correction of printing error of mppcf designation for Talc
(fibrous, nonfibrous and mixtures) in Table AC-3 (Register 85, No. 12).

8. Amendment of Table AC-1 and footnote (j) filed 11-21-86; effective thirtieth
day thereafter (Register 86, No.47).

9. Amendment of subsection (c), (d), (f), Tables AC-1, AC-2 and AC-3 filed 2-3-
87; effective thirtieth day thereafter (Register 87, No. 6).

10. Amendment filed 7-26-90; operative 8-25-90 (Register 91, No. 1).

11. Amendment of Table AC-1 and footnotes to Table AC-1 filed 11-21-90;
operative 12-21-90 (Register 91, No. 1).

12. Editorial correction of graphic correcting spelling of Beryllium and adding
measurements omitted (Register 91, No. 23).

13. Amendment of Table AC-1 and Note filed 4-7-92; operative 5-7-92 (Register
92, No. 14).

14. Editorial correction of printing error repositioning Grain dust (Register
92, No. 34).

15. Amendment of Table AC-1 filed 3-3-93; operative 4-2-93 (Register 93, No.
11).

16. Amendment of Table AC-1 filed 4-30-93; operative 5-31-93 (Register 93,
No. 18).

17. Change without regulatory effect amending Table AC-1 Formaldehyde filed 12-
7-94 pursuant to section 100, title 1, California Code of Regulations
(Register 94, No. 49).

18. Amendment of subsections (a)(2) and (c)(2)(B) and Table AC-1 filed 4-3-95;
operative 5-3-95 (Register 95, No. 14).

19. Editorial corrections (Register 95, No. 24).

20. Change without regulatory effect amending Table AC-1 filed 6-12-95 pursuant
to section 100, title 1, California Code of Regulations (Register 95, No.
24).

21. Change without regulatory effect amending Table AC-1 filed 6-29-95 pursuant
to section 100, title 1, California Code of Regulations (Register 95, No.
26).

22. Editorial correction repositioning "Particulates not otherwise regulated"
(Register 95, No. 35).

23. Amendment of Table AC-1 (1,3 Butadiene) filed 5-29-97; operative 8-27-97
(Register 97, No. 22).

24. Amendment of Table AC-1 (methylene chloride) filed 8-4-97; operative 11-2-
97 (Register 97, No. 32).

25. Change without regulatory effect amending Table AC-1 (silver) filed 1-6-98
pursuant to section 100, title 1, California Code of Regulations (Register
98, No. 2).

26. Change without regulatory effect amending table AC-1 filed 2-16-2000
pursuant to section 100, title 1, California Code of Regulations (Register
2000, No. 7).

27. Change without regulatory effect repealing Appendix footnote (q) filed 6-
27-2000 pursuant to section 100, title 1, California Code of Regulations
(Register 2000, No. 26).

28. Editorial correction of placement of appendix footnote (h) reference
(Register 2000, No. 51).

29. Change without regulatory effect amending subsection (c)(1)(B) and amending
appendix filed 12-21-2000 pursuant to
section 100, title 1, California Code of Regulations (Register 2000, No. 51).

30. Amendment of Table AC-1 filed 1-4-2001; operative 2-3-2001 (Register 2001,
No. 1).

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
section100, 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).

35. Amendment of Table AC-1 filed 10-1-2004; operative 10-31-2004 (Register
2004, No. 40).

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
LaborCode section 142.3(a)(3) (Register 2006, No. 38).

40. Editorial correction of Table AC-1 - Methyl chloride (Register 2007, No. 32).

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