On September 1, 2017, the U.S. Environmental Protection Agency (EPA) proposed
amendments to the Portland Cement Manufacturing Industry National Emission Standards
for Hazardous Air Pollutants.

	Portland cement manufacturing is an energy-intensive process that grinds and heats a
mixture of raw materials such as limestone, clay, sand and iron ore in a rotary kiln. That
product, called clinker, is cooled, ground and then mixed with a small amount of gypsum to
produce cement. The primary use of cement is to produce concrete, formed by mixing
cement with gravel, sand, and water.

	A variety of pollutants are emitted from the burning of fuels and heating of raw materials.
Emissions also can occur from grinding, cooling and materials-handling steps in the
manufacturing process. To control these emissions, the EPA has set maximum achievable
technology (MACT) standards, which include emission limits for particulate matter, non-
dioxin total hydrocarbons, hydrogen chloride, dioxins/furans and mercury.

	After conducting a risk analysis of facility emissions under the fully implemented MACT
standards, the EPA found no appreciable health or ecological risks due to air toxics
emissions and, thus, risks are acceptable. Furthermore, the EPA identified no cost-effective
controls under the technology review to achieve further emission reductions. The EPA is not
proposing any revisions based on the residual risk and technology review.

	This action is proposing amendments to correct and clarify rule requirements and
provisions, which would improve monitoring, compliance and implementation of the rule.
Some of these amendments include:

o Clarifying that the 30-operating day rolling average reporting does not apply to the

dioxins/furans temperature monitoring system,
o Revising and adding clarifying text for the particulate matter testing requirement

for units with inline raw mills,
o Adding an appendix to the rule which includes the 1989 Toxic Equivalency Factors
for dioxins/furans


	The Clean Air Act requires the EPA to regulate toxic air pollutants, also known as air toxics,
from large industrial facilities in two phases.

	The first phase is "technology-based," where the EPA develops standards for controlling the
emissions of air toxics from sources in an industry group (or "source category"). These

maximum achievable control technology (MACT) standards are based on emissions levels
that are already being achieved by the controlled and low-emitting sources in an industry.

	The second phase is a "risk-based" approach called residual risk. Here, the EPA must
determine whether more health-protective standards are necessary. Within 8 years of
setting the MACT standards, the Clean Air Act requires the EPA to assess the remaining
health risks from each source category to determine whether the MACT standards protect
public health with an ample margin of safety, and protect against adverse environmental

	Every 8 years after setting the MACT standards, the Clean Air Act also requires the EPA to
review and revise the standards, if necessary, to account for improvements in air pollution
controls and/or prevention.


	The EPA will accept comments for 30 days after the proposal is published in the Federal

	Comments, identified by Docket ID No. EPA-HQ-OAR-2016-0442 may be submitted by one
of the following methods:

o Go to https://www.regulations.gov/ and follow the on-line instructions for
submitting comments.

o Send comments by email to a-and-r- Docket@epa.gov, Attention Docket ID No. EPA-

o Fax your comments to: 202-566-9744, Attention Docket ID. No. EPA-HQ-OAR-2016-

o Mail your comments to: EPA Docket Center, Environmental Protection Agency, Mail
Code: 28221T, 1200 Pennsylvania Ave., NW, Washington, DC 20460, Attention
Docket ID. No. EPA-HQ-OAR-2016-0442.

o Deliver comments in person to: EPA Docket Center, 1301 Constitution Ave., NW,
Room 3334, Washington, DC. Note: In person deliveries (including courier deliveries)
are only accepted during the Docket's normal hours of operation. Special
arrangements should be made for deliveries of boxed information.