Section 5141.1: wildfire smoke exposure rules for outdoor crews
Section 5141.1 applies where the current AQI for PM2.5 reaches 151 and the employer should reasonably anticipate wildfire smoke exposure. It requires an AQI check each shift, communication, Appendix B training, engineering and administrative controls, and NIOSH-approved respirators offered for voluntary use. Above an AQI of 500, respirator use becomes mandatory under section 5144.
It is 9:40 on a September morning in Butte County. A three-person crew is working a 12 kV lateral that climbs out of a creek bottom into gray pine. A fire forty miles west has been burning for six days, and overnight the plume settled into the drainage and stayed. The trimmer is 45 feet up with a saw running. At the tailboard the foreman opens AirNow on a phone and reads the monitor in the nearest town: 212.
That number, on its own, turns on a safety order filed a long way from the rest of a tree crew's Title 8. It is section 5141.1, Protection from Wildfire Smoke, filed in Article 107 of the General Industry Safety Orders under the heading Dusts, Fumes, Mists, Vapors and Gases.
The section, and the two conditions that turn it on
(1) This section applies to workplaces where: (A) The current Air Quality Index (current AQI) for PM2.5 is 151 or greater, regardless of the AQI for other pollutants; and (B) The employer should reasonably anticipate that employees may be exposed to wildfire smoke.
That is section 5141.1(a)(1) entire. Both conditions have to be met. Each is about the air and the anticipation, so the section reaches any workplace in the state that satisfies them.
Three words in it do real work.
Current. Subsection (b) defines the current AQI as the EPA's real-time reporting method, "also referred to as the 'NowCast.'" The daily AQI a newspaper prints is the wrong number. The crew needs what the monitor is saying now.
PM2.5. The section reads one pollutant and says so: "regardless of the AQI for other pollutants." An AQI of 180 driven by ozone leaves it dormant. AirNow reports a separate PM2.5 value alongside the headline number, and that is the one to read.
Wildfire smoke. Subsection (b) defines it as emissions from fires in "wildlands," as defined in section 3402, or in adjacent developed areas. Section 3402 lives in the firefighter safety orders and defines wildlands as "sparsely populated geographical areas covered primarily by grass, brush, trees, crops, or combination thereof." An almond orchard is wildlands by that definition. A warehouse fire in an industrial district sits outside that definition, and its smoke leaves this section asleep however bad the AQI gets.
Subsection (a)(3) settles what else the crew owes. An employer who complies with 5141.1 is treated as compliant with sections 5141 and 5155 for the limited purpose of wildfire smoke exposure at an AQI of 151 or greater. One calculation covers the whole exposure.
Five exemptions, and the one a chip truck can earn
Subsection (a)(2) exempts five things.
Exemption | What it requires |
(A) Enclosed buildings or structures | Air filtered by a mechanical ventilation system, and the employer ensures windows, doors, bays and other openings stay closed except to enter or exit |
(B) Enclosed vehicles | Air filtered by a cabin air filter, and the employer ensures windows, doors and other openings stay closed except to enter or exit |
(C) Employer measurement | The employer demonstrates by measurement under Appendix A that PM2.5 does not correspond to an AQI of 151 or greater |
(D) One hour or less | Employees exposed to a current AQI for PM2.5 of 151 or greater for a total of one hour or less during a shift |
(E) Wildland firefighters | Firefighters engaged in wildland firefighting |
Nothing there excepts utility work, vegetation management, storm restoration or a crew that moves from span to span. A line clearance contractor gets the same five as everybody else.
Two of them are worth reading closely, because a tree crew claims them occasionally and loses them easily.
The chip truck cab qualifies under (B) while the cabin air filter is doing its job and the windows are up. The duty is on the employer to ensure they stay up. Windows down between jobs puts the crew back inside the section. The bucket of an aerial lift stands in open air the whole time, whatever the boom is insulated to.
The one-hour exemption in (D) measures exposure, not outdoor time. A patroller who drives a circuit in a filtered cab and steps out at six structures for eight minutes each has forty-eight minutes of exposure and is under the line. The seventh structure puts them over it, and every duty in the section lands at once. It is a threshold, and it is crossed whole. A trimmer working a span for a morning is hours past it.
The AQI check, at the start of every shift
The employer shall determine employee exposure to PM2.5 for worksites covered by this section at the start of each shift and periodically thereafter, as needed to protect the health of employees, by any of the following methods:
Three methods follow, and subsection (c)(1) lists six places to get the number.
U.S. EPA AirNow
The Interagency Wildland Fire Air Quality Response Program
The U.S. Forest Service
The California Air Resources Board
The local air pollution control district
The local air quality management district
Method (1) is checking those websites. Method (2) is obtaining the same values from the same agencies by telephone, email, text "or other effective method." Method (3) is measuring PM2.5 at the worksite and converting it under Appendix A.
The section leaves "periodically thereafter" open, and Cal/OSHA's guidance page leaves it open too. The employer picks the frequency, the compliance officer judges whether it was "as needed to protect the health of employees," and the Occupational Safety and Health Appeals Board decides it on appeal. A plume that moved into a drainage overnight can move back out by noon, and a single 9:40 reading standing for a ten-hour day is the version that gets cited.
Method (3) exists because of exactly the Butte County problem. The monitor the phone reports may be twenty miles away and two thousand feet lower, in a different air mass than the crew. An employer that wants a number for the span itself has to buy a direct-reading instrument and run it under Appendix A, which brings its own arithmetic. That is the subject of a later section here, and the answer it gives can differ from the one on the phone.
The exception to subsection (c) lets an employer skip the determination in two cases.
1. The employer assumes the current AQI for PM2.5 is greater than 500 and complies with subsection (f) using that assumption; or 2. In an emergency subject to subsection (f)(4), the employer assumes the current AQI for PM2.5 is 151 or greater and complies with subsection (f)(3)(A) using that assumption.
Both are opt-ins to a higher duty. The second one matters to this trade, and it is covered below.
What the crew is told, and what it reports
Subsection (d) runs in two directions, and both are hung on the injury and illness prevention program.
As required by section 3203, the employer shall establish and implement a system for communicating wildfire smoke hazards in a language and manner readily understandable by employees, including provisions designed to encourage employees to inform the employer of wildfire smoke hazards at the worksite without fear of reprisal.
Downward, the system has to inform employees of the current AQI for PM2.5 determined under subsection (c), and of the protective measures available to them. Upward, it has to encourage employees to report worsening air quality and adverse symptoms, which subsection (d)(2)(B) names: "asthma attacks, difficulty breathing, and chest pain."
The "as required by section 3203" opening does real work. It files the communication duty inside the IIPP, which is where the documentation obligation comes from.
On a line clearance crew the downward half has a practical shape. The trimmer 45 feet up has both hands on a saw, and the foreman is the relay. The upward half has a harder one. A report of difficulty breathing from a climber in a saddle raises one question, which is whether that person can still descend under their own power. What happens next belongs to a separate duty. See aerial rescue readiness for who has to be standing by, and what they have to be able to do.
Appendix B, and the two blanks in it
Subsection (e) requires effective training and instruction containing, at a minimum, the information in Appendix B. The appendix is headed "Information to Be Provided to Employees (Mandatory)" and carries eight lettered topics.
Topic | |
(a) | The health effects of wildfire smoke |
(b) | The right to obtain medical treatment without fear of reprisal |
(c) | How employees can obtain the current AQI for PM2.5 |
(d) | The requirements of Title 8, section 5141.1 |
(e) | The employer's two-way communication system |
(f) | The employer's methods to protect employees from wildfire smoke |
(g) | The importance, limitations, and benefits of using a respirator when exposed to wildfire smoke |
(h) | How to properly put on and use the respirators provided by the employer |
Two of those eight are printed in the appendix as fill-in lines. Under (e) the regulation prints "The employer's communication system is: _____________________." Under (f) it prints "The employer's control system at this worksite is: __________." A mandatory appendix with blanks in it is telling the employer to supply two answers of its own, and the phrase "at this worksite" in the second blank says so twice.
Appendix B also does a job inside section 5144. Subsection (f)(3)(A) directs that "Employers shall use Appendix B to this section in lieu of Appendix D to section 5144 for training regarding voluntary use of respirators." A crew trained to Appendix B has been given the voluntary-use information section 5144 requires, and no separate Appendix D handout is owed.
Three sentences in the appendix get quoted back at employers more than any others.
Surgical masks or items worn over the nose and mouth such as scarves, T-shirts, and bandannas will not provide protection against wildfire smoke. An N95 filtering facepiece respirator, shown in the image below, is the minimum level of protection for wildfire smoke.
And on fit:
The manufacturer's instructions must be followed except for medical evaluations, fit testing, and shaving of facial hair, which are recommended but not required for voluntary use of filtering facepiece respirators.
That last sentence is the one to read twice before writing a beard policy into a smoke plan. The appendix recommends shaving, stops short of requiring it, and offers the alternative in the same paragraph: "Loose-fitting powered air purifying respirators may be worn by people with facial hair since they do not have seals that are affected by facial hair."
Engineering, then administrative, then the respirator
Subsection (f) sets a hierarchy and runs it in order.
(1) Engineering Controls. The employer shall reduce employee exposure to PM2.5 to less than a current AQI of 151 by engineering controls whenever feasible, for instance by providing enclosed buildings, structures, or vehicles where the air is filtered. If engineering controls are not sufficient to reduce exposure to PM2.5 to less than a current AQI of 151, then the employer shall reduce employee exposures to the extent feasible.
On a span, the engineering control the regulation names is a filtered cab, and the work is 45 feet up a gray pine. The honest answer for aloft work is that engineering controls run out, and the section anticipates that. Its second sentence still asks for reduction "to the extent feasible," which on a crew means rotating people into the cab between climbs.
(2) Administrative Controls. Whenever engineering controls are not feasible or do not reduce employee exposures to PM2.5 to less than a current AQI of 151, the employer shall implement administrative controls, if practicable, such as relocating work to a location where the current AQI for PM2.5 is lower, changing work schedules, reducing work intensity, or providing additional rest periods.
All four of those are real on a scheduled pruning cycle. A contractor with three counties of work on the books can move crews to the one out from under the plume, start at 5:30 to work the cleaner morning air, cut the number of climbs per person, and add rest periods.
Those rest periods stack on top of the heat illness duty. The cool-down rest in section 3395 is the employee's on request and has its own trigger, covered in section 3395 on a vegetation crew. September in the northern Sacramento Valley routinely puts a crew under both sections at once, and the arithmetic is additive.
Subsection (f) controls the exposure and leaves the job running. The stop-work rule for this trade is section 2951(f), and its list is specific:
With the exception of emergency restoration procedures, line clearance tree trimming work shall not be performed when adverse weather conditions such as thunderstorms in the immediate vicinity, high winds, snow storms or ice storms, make the work hazardous in spite of the work practices required by this section.
Thunderstorms, high winds, snow, ice. Those four are the list entire, and smoke sits outside it alongside visibility. Section 2951 and the other eight subsections that govern the crew's day are covered in the section 2951 guide. For smoke, the duty is to control the exposure under 5141.1(f), and a decision to send the crew home stays the employer's own.
Voluntary at 151, and the program a mandate buys
Where the current AQI for PM2.5 is equal to or greater than 151, but does not exceed 500, the employer shall provide a sufficient number of respirators to all employees for voluntary use in accordance with section 5144 and encourage employees to use respirators. Respirators shall be NIOSH-approved devices that effectively protect the wearers from inhalation of PM2.5, such as N95 filtering facepiece respirators. Respirators shall be cleaned or replaced as appropriate, stored, and maintained, so that they do not present a health hazard to users.
Two duties sit in that paragraph, and both carry qualifiers. Provide a sufficient number of respirators to all employees, and encourage employees to use them. A duty to make anyone wear one is absent, so between 151 and 500 the employee decides.
Cal/OSHA's guidance page names the acceptable labels: "respirators must be labeled N-95, N-99, N-100, R-95, P-95, P-99, or P-100, and must be labeled as approved by the US National Institute for Occupational Safety and Health (NIOSH)." Every respirator handed out has to carry one of those labels.
The note attached to subsection (f)(3)(A) is what makes the voluntary route cheap:
NOTE: For those employees whose only use of respirators involves the voluntary use of filtering facepieces, such as N95 respirators, fit testing and medical evaluations are not required by section 5144.
Section 5144 says the same thing from the other side. The exception to 5144(c)(2)(B) relieves the employer of including in a written respiratory protection program "those employees whose only use of respirators involves the voluntary use of filtering facepieces (dust masks)."
Here is the trap, and it is the one real mistake this page exists to prevent. A safety manager reads all of the above, decides the voluntary framing is soft, and writes into the contractor's plan: N95 required above AQI 200. That sentence does not tighten 5141.1. It moves the crew into section 5144(c)(1):
In any workplace where respirators are necessary to protect the health of the employee or whenever respirators are required by the employer, the employer shall establish and implement a written respiratory protection program with worksite-specific procedures.
"Required by the employer" is the operative phrase, and it is the employer's own rule that satisfies it. The program that follows has nine listed elements, including medical evaluations, fit testing procedures for tight-fitting respirators, cleaning and storage schedules, and a designated program administrator.
Every climber and groundman on that crew now needs a medical evaluation and an annual fit test, and facial hair becomes a disqualification rather than a recommendation. An employer that wants people in N95s at AQI 200 can have that, so long as it knows it has bought the program to go with it. The respirator is also protective equipment, and where the rest of the crew's PPE is written is covered in chainsaw PPE on a California line clearance job.
Above 500 the voluntary part ends
Where the current AQI for PM2.5 exceeds 500, respirator use is required. Respirators shall be used in accordance with section 5144. The employer shall provide respirators with an assigned protection factor, as listed in section 5144, such that the PM2.5 levels inside the respirator correspond to an AQI less than 151.
Three things change at once. Use becomes mandatory. Section 5144 applies in full, which is the written program described above. And the respirator gets selected by arithmetic.
That arithmetic is short. An AQI of 151 corresponds to 55.5 micrograms per cubic meter, so the air inside the facepiece has to be below that figure. Table 1 of section 5144 gives an air-purifying half mask an assigned protection factor of 10, and footnote 3 confirms "This APF category includes filtering facepieces, and half masks with elastomeric facepieces."
An N95 at an APF of 10 keeps the inside below 55.5 micrograms up to an ambient 555. Above that the crew needs something with a higher factor. A full facepiece air-purifying respirator is 50, and a powered air-purifying respirator with a half mask is also 50.
An employer can also skip the whole determination and land here voluntarily. The first exception to subsection (c) lets an employer assume the AQI exceeds 500 and comply with subsection (f) on that assumption, which means a full respirator program every day and the monitoring question closed. It is an expensive way to run a crew, and it is available.
The emergency clause names utilities by name
Subsection (f)(4) is the provision in this section most likely to govern a line clearance crew on its worst week of the year.
(4) Emergencies. The following applies to emergency operations, including rescue and evacuation. The following also applies to utilities, communications, and medical operations that are directly aiding emergency operations or firefighting operations. (A) The employer shall comply with subsection (f)(3)(A) for all AQI levels equal to or greater than 151. (B) Subsection (f)(1), (f)(2), and (f)(3)(B) do not apply.
Read what survives and what falls away.
Subsection | Ordinary work | Work under (f)(4) |
(f)(1) Engineering controls | Required whenever feasible | Does not apply |
(f)(2) Administrative controls | Required if practicable | Does not apply |
(f)(3)(A) Respirators for voluntary use | AQI 151 through 500 | All AQI levels of 151 or greater |
(f)(3)(B) Required respirator use above 500 | Applies | Does not apply |
A crew clearing a burned-over circuit so a utility can restore it, or cutting a leaner off an energized primary so a strike team can get an engine down a road, is doing utility work directly aiding emergency or firefighting operations. The hierarchy that told the employer to relocate the work falls away, because the work sits where the fire put it.
What remains is the duty to hand out respirators and encourage their use, and that duty now runs to every AQI above 151. At an AQI of 700 the employer still owes provision and encouragement, and the wearing still rests with the employee.
Pair (f)(4) with the second exception to subsection (c) and the pre-shift routine collapses to one decision. In an emergency subject to (f)(4), the employer may assume the AQI is 151 or greater and comply with (f)(3)(A) on that assumption. Respirators go on the truck for everyone, every shift, for the duration, and the phone stays in the pocket.
Where this gets argued is the word "directly." A crew restoring a circuit behind the fire line at the utility's direction is plainly inside. A crew on a routine four-year cycle in the next county, under the same plume, working a circuit nothing has happened to, is plainly outside, and owes the full hierarchy in (f)(1) and (f)(2).
Between those two sits a large middle: hazard tree removal ordered during a Public Safety Power Shutoff, patrol work on a circuit that may be re-energized, standby crews staged at an incident base. The section is silent on all of it. The compliance officer draws the line at the inspection, and the Appeals Board redraws it on appeal. A contractor that wants to rely on (f)(4) should be able to name the utility's request, the incident, and the date on which the crew was assigned to it.
One meter reading of 500.4 micrograms, and four different answers
Appendix A is headed "Measuring PM2.5 Levels at the Worksite (Mandatory if an Employer Monitors with a Direct Reading Instrument)." An employer that buys a monitor is bound by it. It sets the instrument specification first. The monitor must measure particles "ranging from an aerodynamic diameter of 0.3 micrometers or less up to and including 2.5 micrometers."
It then puts a person behind the instrument. Whoever supervises the monitoring must have "the training or experience necessary to apply this section and to ensure the correct use of the monitor and the interpretation of the results, so that exposures are not underestimated."
Then it prints a conversion table, and the table is where the trouble is.
PM2.5 in µg/m³ | Cal/OSHA Appendix A says | EPA's current Table 2 says |
0 to 12.0 | AQI 0 to 50 | 0.0 to 9.0 is AQI 0 to 50 |
12.1 to 35.4 | AQI 51 to 100 | 9.1 to 35.4 is AQI 51 to 100 |
35.5 to 55.4 | AQI 101 to 150 | 35.5 to 55.4 is AQI 101 to 150 |
55.5 to 150.4 | AQI 151 to 200 | 55.5 to 125.4 is AQI 151 to 200 |
150.5 to 250.4 | AQI 201 to 300 | 125.5 to 225.4 is AQI 201 to 300 |
250.5 to 500.4 | AQI 301 to 500 | 225.5 and above is AQI 301 and above |
Appendix A was adopted with the rest of the section on February 1, 2021, against the EPA breakpoints in force at the time. The EPA revised those breakpoints in Appendix G to 40 CFR Part 58, published at 89 FR 16403 on March 6, 2024. Appendix A has not been amended since.
At the trigger that matters most, the two still agree exactly. Both put an AQI of 151 at 55.5 micrograms per cubic meter, and both put 101 at 35.5. Whether section 5141.1 applies at all is the same question under either table.
Above that they part, and at the top they part badly. Footnote 4 to the EPA's Table 2 says that AQI values above 500 are calculated using the concentration specified for an AQI of 500, and for PM2.5 that concentration is 325.4 micrograms per cubic meter. Appendix A's top row runs to 500.4 micrograms and calls it 500.
So take one direct-reading instrument, sitting under the same gray pine, showing 500.4 micrograms per cubic meter.
Who is reading it | What that reading is | What is owed |
Cal/OSHA Appendix A | AQI 500 | Voluntary respirators under 5141.1(f)(3)(A); the required-use gate at (f)(3)(B) is "exceeds 500" and has not been crossed |
The EPA's current Table 2 | Above AQI 500, since the 500 mark sits at 325.4 µg/m³ | The EPA governs reporting rather than workplaces |
Oregon, OAR 437-002-1081(7)(d) | "at or above 500.4 µg/m3 (AQI 501)" | Required respirator use under a full 29 CFR 1910.134 program |
Washington, WAC 296-820-840(4)(a) | "500.4 µg/m3 to 554.9 µg/m3 (AQI 849 to 957)" | Required use and enrollment in a complete respiratory protection program under chapter 296-842 WAC |
The same instrument, the same reading, and Washington's rule calls it AQI 849 where California's calls it 500. Washington converted with the EPA's current equation; Oregon and California converted with the one in force before March 2024. Each state is right about its own rule. They are answering with different arithmetic.
Two practical consequences follow for a California crew.
The first is that Appendix A's table stops at 500.4 micrograms, so 500 is the highest number an employer measuring on site can produce from it. In practice the required-use gate for a direct-reading employer is a measurement above 500.4 micrograms per cubic meter, which is the sensible reading, and the text leaves it unstated.
The second is that the answer now depends on which of the three methods in subsection (c) the employer chose. An employer reading AirNow sees the EPA's current scale and crosses 500 at roughly 325 micrograms. An employer reading its own monitor and converting under Appendix A crosses it at 500.4.
Both methods are expressly permitted by subsection (c). The section is silent on which one governs when they disagree, and until Cal/OSHA amends Appendix A or issues an interpretation, the conservative course is to act on whichever number is higher.
A revision may be coming, for a different reason. Labor Code section 6721(b) required the Division, before December 1, 2025, to submit a rulemaking proposal to the Standards Board to consider revising both section 3395 and section 5141.1.
The wildfire smoke half of that directive is written narrowly: it addresses farmworkers, and it aims to reduce the AQI at which respirator use becomes mandatory for farmworkers to at most 301. The Division has run advisory meetings on it. Section 5141.1 as published carries no amendment after February 1, 2021, so the text above is the text that governs.
No federal standard sets a limit for smoke
There is no federal standard setting an exposure limit for wildfire smoke. Paragraph 1910.269(r) is where federal line clearance requirements live, and OSHA's own eTool describes its reach: "The standard 1910.269(r) addresses both personnel and equipment requirements." Air contaminants are not among them. The tiers that paragraph does set are covered in the 1910.269(r) tiers guide.
OSHA's Wildfires safety and health topics page names no exposure limit either. It states that "Employers are required to protect workers from the anticipated hazards associated with the response and recovery operations for wildfires that workers are likely to conduct," and links out to CDC materials on wildland fire smoke.
What that leaves a federal-jurisdiction employer is two things. Section 1910.134 governs respirators once they are required or voluntarily provided, on the same logic Cal/OSHA's 5144 uses. And Section 5(a)(1) of the OSH Act remains available: OSHA's June 30, 2021 inspection guidance for tree care and tree removal operations tells compliance officers that citations may be issued under the General Duty Clause.
For a contractor that mobilizes across the West, the shape of the map is worth knowing. California, Oregon and Washington each have a standard. Oregon's OAR 437-002-1081 applies at 35.5 micrograms per cubic meter, an AQI of 101, and was filed as Administrative Order 4-2022 on May 10, 2022, effective July 1, 2022.
Washington's chapter 296-820 WAC took effect January 15, 2024 and was amended effective May 16, 2025; it requires effective exposure controls at 35.5 micrograms and encourages them at 20.5. Both trigger at an AQI of 101, fifty points below the level at which California's section wakes up. A crew that crosses the Oregon line under a plume moves into a rule that starts fifty AQI points lower.
What the file has to show
Section 5141.1 has no recordkeeping subsection. Every record it produces comes from somewhere else, and the route runs through section 3203.
Subsection (e) makes the training a section 3203 obligation, which pulls in section 3203(b)(2):
Documentation of safety and health training required by subsection (a)(7) for each employee, including employee name or other identifier, training dates, type(s) of training, and training providers. This documentation shall be maintained for at least one (1) year.
Four fields, one year. That is the whole of the mandatory record for wildfire smoke.
For one trimmer on one smoke event, a defensible file holds five things.
A training record naming that trimmer, the date trained, "Protection from Wildfire Smoke, 8 CCR 5141.1 Appendix B" as the type, and the trainer.
The Appendix B handout given to them, with both blanks filled in: the employer's communication system, and the control system at that worksite.
The AQI determination for the shift: the value, the time, the source, and who took it.
A record that respirators were made available, and which model.
If the employer is relying on subsection (f)(4), what the crew was assigned to and who assigned it.
Only the first of those five is expressly required. The other four rest on the employer's own practice, which is exactly why they go missing. The AQI determination is the conspicuous one: subsection (c) requires the employer to make it at the start of each shift and periodically after, and a determination that was never written down is a determination the employer cannot prove it made. How the rest of a crew's qualification file is built, and how long each piece has to live, is covered in documenting qualification.
Where it bites
One reading for a ten-hour shift. Subsection (c) requires a start-of-shift determination and periodic ones after. A single morning number in the file answers the first half of that requirement and leaves the second half open.
A required-use rule written locally. "N95 required above AQI 200" in a contractor safety manual triggers section 5144(c)(1) and everything behind it: written program, medical evaluations, fit testing, program administrator. The voluntary route at 5141.1(f)(3)(A) was designed to avoid all of that.
Appendix B handed out with the blanks empty. The appendix is mandatory and it prints two fill-in lines. The employer's own communication system belongs in that blank, in the employer's own words, and the phrase "at this worksite" is in the regulation.
Claiming (f)(4) for routine cycle work. The emergency clause covers utilities "directly aiding emergency operations or firefighting operations." A scheduled prune under a distant plume does not qualify, and the employer still owes (f)(1) and (f)(2).
A monitor bought without Appendix A. Direct reading is a permitted method and it is mandatory-if-used. The instrument specification, the conversion table and the trained supervisor all come with it.
Assuming the phone and the meter agree above AQI 151. They diverge, and the gap widens the worse the air gets. Know which method produced the number in the file.
Further reading
Section 2951: the nine subsections that govern a line clearance crew's day: The adverse weather list that stops work, and the four conditions it names. Smoke is not one of them.
Section 3395: heat illness prevention on a vegetation crew: The cool-down rest that a smoke-driven extra rest period has to be layered on top of, not substituted for.
Aerial rescue readiness on a line clearance crew: What happens when the symptom report in section 5141.1(d)(2)(B) comes from 45 feet up.
Frequently asked questions
Does section 5141.1 apply to line clearance tree trimming?
Yes. Section 5141.1(a)(1) applies to workplaces where the current AQI for PM2.5 is 151 or greater and the employer should reasonably anticipate that employees may be exposed to wildfire smoke. The five exemptions in section 5141.1(a)(2) cover enclosed buildings, enclosed filtered vehicles, employers who measure PM2.5 themselves under Appendix A, exposure of one hour or less in a shift, and firefighters engaged in wildland firefighting. Nothing in the section excepts utility work, vegetation management or emergency restoration.
At what AQI does a crew have to wear a respirator in California?
Wearing is required only above a current AQI for PM2.5 of 500. Between 151 and 500 the employer must provide a sufficient number of NIOSH-approved respirators for voluntary use under section 5141.1(f)(3)(A) and encourage employees to use them, and the employee decides. Above 500, section 5141.1(f)(3)(B) requires use in accordance with section 5144, which brings a written program, medical evaluation and fit testing with it.
Can an employer just require N95s at a lower AQI to keep it simple?
It can, and it should understand the cost. Section 5144(c)(1) requires a written respiratory protection program with worksite-specific procedures in any workplace where respirators are necessary or whenever respirators are required by the employer. Writing a required-use rule at AQI 200 into a contractor safety manual triggers that program, including medical evaluations and fit testing, which the voluntary route at section 5141.1(f)(3)(A) does not.
Does the wildfire smoke rule still apply during emergency restoration?
Part of it. Section 5141.1(f)(4) applies to emergency operations and to utilities, communications and medical operations directly aiding emergency operations or firefighting operations. In that work the employer must comply with subsection (f)(3)(A), providing respirators for voluntary use, at all AQI levels of 151 or greater. Subsections (f)(1), (f)(2) and (f)(3)(B) do not apply, so the engineering and administrative control duties and the above-500 mandatory use requirement drop out.
Do the training and AQI records have to be kept?
Section 5141.1 has no recordkeeping subsection of its own. Its training duty in subsection (e) runs through section 3203, and section 3203(b)(2) requires documentation of safety and health training for each employee including the employee name or other identifier, training dates, types of training and training providers, maintained for at least one year. The AQI determinations required by subsection (c) carry no prescribed record.
