South Coast air regulators will consider new dust-control rules on September 4 for aggregate operations and construction and demolition debris transfer stations. The proposal would add registration, equipment, sign, inspection, and recordkeeping duties across the region.
The amendments are not law. South Coast AQMD's Governing Board must vote before they can take effect. Written comments for the meeting are due to the agency's clerk by 5 p.m. on September 1.
Which businesses would be covered
Rule 1157 now applies to permanent and temporary aggregate and related operations. Those include businesses that produce or use sand, gravel, cement, crushed stone, quarried rock, or crushed base material, as well as some inert landfills.
The proposal would expand the rule to construction and demolition debris transfer stations. A transfer station already covered by Rule 410 for odors would remain outside Rule 1157 under the proposed exemption.
South Coast AQMD estimates that the amended rule would cover 862 facilities. The agency identified 438 in Los Angeles County and 156 in Orange County. It says 177 construction and demolition debris transfer stations would be newly added.
The staff report also estimates that up to 440 of the covered facilities may qualify as small businesses under the U.S. Small Business Administration definition. Different small-business definitions produce lower counts.
What transfer stations would have to add
If the board adopts the package as written, a construction and demolition debris transfer station would have to register with South Coast AQMD. The proposed deadline is six months after the rule amendment or three months after the start of a new operation, whichever is later.
The proposal would also require transfer stations to:
- Control track-out. Material carried onto a road by vehicle tires or undercarriages could not extend 15 feet or more in cumulative length from the facility exit.
- Install exit controls. Covered stations would need rumble grates and gravel pads that meet the proposed size and maintenance standards.
- Clean spills quickly. Material spilled on an internal paved road would have to be removed within one hour after it is identified.
- Keep records. The operator would have to document truck activity, dust-control work, spills, inspections, and other information listed in the rule.
- Post signs. Required signs would give drivers operating instructions and tell the public how to report dust or other air-quality concerns.
The proposal says transfer stations would not become subject to the new Rule 1157 duties until six months after adoption. Because the board has not acted, the packet uses a six-month placeholder rather than a fixed calendar date.
What would change for existing aggregate operations
The package also adds more specific operating standards for businesses already covered by Rule 1157.
Open storage piles would need dust suppressant at set intervals or documented inspections under an alternate path. Extra irrigation requirements would apply to certain piles near sensitive receptors or a public road. The proposal also sets detailed schedules for cleaning internal roads, removing track-out, replacing gravel pads, inspecting equipment, and repairing identified problems.
The rule would keep its existing limits on visible dust and add a track-out limit. It would also require more records so an operator can show when inspections, watering, sweeping, cleanup, or repairs occurred.
Repeated validated violations could trigger added controls. Depending on the violation history and facility conditions, those controls could include a wind barrier, a non-porous wall, additional wheel or truck washing equipment, or paving internal roads. These provisions use a rolling 36-month period and do not start from an allegation alone. The notice of violation must be finally resolved through a settlement with a civil penalty or a court judgment before it counts as validated under the proposal.
What the agency estimates it would cost
South Coast AQMD's cost figures are planning estimates, not quotes or fees that every facility would pay.
For the 177 transfer stations, the staff analysis assumes about $7,700 to buy and install one set of rumble grates and about $2,200 for a gravel pad at an average facility. Actual needs can change with the number and width of exits.
The analysis assumes four required signs at each of the 862 facilities, at an estimated installed cost of about $4,961 per facility. It also estimates a plan-filing fee of no more than $280.15 for each transfer station under a worst-case assumption that every station is a major source. Staff says actual registration fees are likely to be lower.
Across all covered facilities, the agency estimates an average annual implementation cost of about $378,609 to $475,292 from 2027 through 2051, depending on the interest-rate assumption. That is a regional total. It is not a per-facility cost.
What remains unsettled
The board can adopt, change, continue, or reject the proposal on September 4. Until it acts, the existing Rule 1157 remains controlling and construction and demolition debris transfer stations are not covered by the proposed expansion.
An exact compliance date also remains unsettled. The final proposed text ties the new duties to the date of adoption, so a calendar date cannot be confirmed before the vote.
The practical takeaway
An aggregate operator or construction and demolition debris transfer station in the South Coast AQMD region can use the final proposal to map possible work without treating it as current law.
Start by listing facility exits, internal paved and unpaved roads, open storage piles, nearby public roads and sensitive receptors, existing rumble grates or wash equipment, and current inspection records. Compare that list with the proposed rule and note where equipment, signs, or records may need to change.
Wait for the September 4 action before treating the proposal as a compliance duty. If the board adopts it, confirm the final text, adoption date, and any changes made at the hearing before ordering equipment or calculating a filing deadline.