OAR 437-003-1000
Oregon Rules for Air Contaminants

An employee’s exposure to any substance listed in Oregon Tables Z-1, Z-2, or Z-3 of this section shall be limited in accordance with the requirements of the following paragraphs of this section.
(1) Oregon Table Z-1.
(a) Substances with limits preceded by “C” – Ceiling Values. An employee’s exposure to any substance in Oregon Table Z-1, the exposure limit of which is preceded by a “C”, shall at no time exceed the exposure limit given for that substance. If instantaneous monitoring is not feasible, then the ceiling shall be assessed as a 15-minute time weighted average exposure which shall not be exceeded at any time during the working day.
(b) Other substances – 8-hour Time Weighted Averages. An employee’s exposure to any substance in Oregon Table Z-1, the exposure limit of which is not preceded by a “C”, shall not exceed the 8-hour Time Weighted Average given for that substance in any 8-hour work shift of a 40-hour work week.
(c) Other Substances – Excursion Limits. Excursions in worker exposure levels may exceed 3 times the PEL-TWA for no more than a total of 30 minutes during a workday, and under no circumstances should they exceed 5 times the PEL-TWA, provided that the PEL-TWA is not exceeded.
(d) Skin Designation. To prevent or reduce skin absorption, an employee’s skin exposure to substances listed in Oregon Table Z-1 with an “X” in the Skin Designation column following the substance name shall be prevented or reduced to the extent necessary in the circumstances through the use of gloves, coveralls, goggles, or other appropriate personal protective equipment, engineering controls or work practices.
(2) Oregon Table Z-2. An employee’s exposure to any substance listed in Oregon Table Z‑2 shall not exceed the exposure limits specified as follows:
(a) 8-hour time weighted averages. An employee’s exposure to any substance listed in Oregon Table Z-2, in any 8-hour work shift of a 40-hour work week, shall not exceed the 8-hour time weighted average limit given for that substance in Oregon Table Z-2.
(b) Acceptable ceiling concentrations. An employee’s exposure to a substance listed in Oregon Table Z-2 shall not exceed the acceptable ceiling concentration for the given substance in the table at any time during an 8-hour shift except: Acceptable maximum peak above the acceptable ceiling concentration for an 8-hour shift. An employee’s exposure to a substance listed in Oregon Table Z-2 shall not exceed the acceptable maximum peak above the acceptable ceiling concentration, and shall not exceed the maximum duration for the given substance during an 8-hour shift.
(c) Example.
(d) Skin Designation. To prevent or reduce skin absorption, an employee’s skin exposure to substances listed in Oregon Table Z-2 with an “X” in the Skin Designation column following the substance name shall be prevented or reduced to the extent necessary in the circumstances through the use of gloves, coveralls, goggles, or other appropriate personal protective equipment, engineering controls or work practices.
(3) Oregon Table Z-3. An employee’s exposure to any substance listed in Oregon Table Z‑3, in any 8-hour work shift of a 40-hour work week, shall not exceed the 8-hour time weighted average limit given for that substance in the table.
(4) Computation formulae. The computation formula which shall apply to employee exposure to more than one substance for which 8-hour time weighted averages are included in OAR 437, Division 2/Z, Toxic and Hazardous Substances, in order to determine whether an employee is exposed over the regulatory limit is as follows:
(a) Cumulative Exposures.
(i) The cumulative exposure for an 8-hour work shift shall be computed as follows:
(ii) To illustrate the formula prescribed in paragraph (4)(a)(i) of this section, assume that Substance A has an 8-hour time weighted average limit of 100 ppm (Oregon Table Z-1). Assume that an employee is subject to the following exposure:
(b) Mixtures.
(i) In case of a mixture of air contaminants an employer shall compute the equivalent exposure as follows:
(ii) To illustrate the formula prescribed in paragraph (4)(b)(i) of this section, consider the following exposures:
(5) To achieve compliance with paragraphs (1) through (4) of this section, administrative or engineering controls must first be determined and implemented whenever feasible. When such controls are not feasible to achieve full compliance, protective equipment or any other protective measures shall be used to keep the exposure of employees to air contaminants within the limits prescribed in this section. Any equipment and/or technical measures used for this purpose must be approved for each particular use by a competent industrial hygienist or other technically qualified person. Whenever respirators are used, their use shall comply with 1910.134.
[ED. NOTE: To view attachments referenced in rule text, click here to view rule.]

Source: Rule 437-003-1000 — Oregon Rules for Air Contaminants, https://secure.­sos.­state.­or.­us/oard/view.­action?ruleNumber=437-003-1000 (accessed May 26, 2025).

437–003–0001
Adoption by Reference 437–003–0003
Purpose 437–003–0005
Additional Applicability 437–003–0006
General Oregon Definitions 437–003–0007
Additional Rules of Practice for Administrative Adjudications 437–003–0011
Additional Definitions 437–003–0015
Drinking Water 437–003–0017
Additional Definitions to Concrete and Masonry Construction 437–003–0020
Toilets 437–003–0027
Applicable Rules 437–003–0037
Acceptable Equipment 437–003–0045
Additional Definitions 437–003–0047
Working Near Overhead High Voltage Lines and Equipment 437–003–0062
Lead Respiratory Protection Program 437–003–0065
Extension Ladders 437–003–0071
Manually Propelled Elevating Aerial Platforms 437–003–0073
Boom Supported Elevating Work Platforms 437–003–0074
Scissor Lifts — Self-Propelled Elevating Work Platforms 437–003–0080
Wind Velocity Device 437–003–0085
General Requirement 437–003–0090
Pinchpoints 437–003–0094
Personnel Platforms 437–003–0096
Underground Installations 437–003–0134
Personal Protective Equipment 437–003–0404
Branch Circuits 437–003–0420
Traffic Control 437–003–0502
Personal Fall Restraint 437–003–0503
Training Requirements 437–003–0706
Protection of Employees On or Near Masonry Walls 437–003–0752
Site-Specific Erection Plan 437–003–0753
Tag Lines 437–003–0761
Additional Training Requirements 437–003–0905
Flooring 437–003–0910
Temporary Floors 437–003–0915
Shoring, Bracing or Guying of Structures 437–003–0920
Project Plans 437–003–0925
Powder-Actuated Tools 437–003–1000
Oregon Rules for Air Contaminants 437–003–1101
Asbestos Respiratory Protection Program 437–003–1127
Cadmium Respiratory Protection Program 437–003–1423
Fall Protection 437–003–1500
Additional Definitions 437–003–1501
Fall Protection 437–003–1502
Warning Line Systems for Roofing Work 437–003–1752
Written Notifications 437–003–1754
Roof and floor holes and openings 437–003–2501
Protection From Falling Objects 437–003–2502
Safety Monitoring Systems 437–003–3060
Methylenedianiline Respiratory Protection Program 437–003–3224
Vehicle Drivers and Riders 437–003–3225
Vehicles for Highway and Road Operation Characteristics and Maintenance 437–003–3226
Vehicles for Use on Property Other Than Public Roads and Highways Operation, Characteristics and Maintenance 437–003–3600
Equipment

May 26, 2025

Rule 437-003-1000's source at or​.us