Tariffs on Canadian & Mexican Crushed Stone: Current Policies and Potential Outcomes

Tariffs on Canadian & Mexican Crushed Stone: Current Policies

No special U.S. tariffs currently apply to construction aggregates like crushed stone from Canada or Mexico under normal trade rules. Crushed stone (HS 2517) enters the U.S. duty‐free under Most Favored Nation rates (Mineral Commodity Summaries 2024), and the US–Mexico–Canada Agreement (USMCA) preserves zero tariffs on originating aggregates. In other words, imports of crushed stone from Canada and Mexico face a 0% tariff as long as they meet USMCA’s rules of origin (Mineral Commodity Summaries 2024).

Recent trade disputes have not specifically targeted aggregates, so Canadian and Mexican stone shipments remain free of import duty. For example, the 2018–2019 U.S. tariffs on steel/aluminum and various Section 301 tariffs did not include raw aggregates. However, broad tariff threats have arisen during trade tensions – notably, in mid-2019 the Trump administration threatened a 5% (rising to 25%) blanket tariff on all Mexican imports (which would have included aggregates) over immigration issues (President Trump Threatens Tariffs on All Goods Imported from Mexico to Address “Border Crisis” | White & Case LLP). That tariff was averted by a bilateral agreement, leaving aggregate imports unaffected.

More recently, industry observers have raised concerns that any future tariff measures against Canada or Mexico could encompass aggregates unless explicitly exempted. In early 2025, for instance, there were proposals of a 25% tariff on all imports from Canada and Mexico as part of broader trade measures (President Trump Imposes 25% Tariffs on Canada and Mexico, and 10% Tariffs on China | White & Case LLP). The National Stone, Sand & Gravel Association (NSSGA) has urged policymakers to exclude aggregates from any such tariffs, warning of harmful side effects. Overall, current U.S. policy imposes no import duty on crushed stone from Canada or Mexico, but the industry remains vigilant that new trade measures could change this, and it is actively lobbying to keep crucial aggregates tariff-free.

Import Volumes from Canada and Mexico

Although the U.S. produces the vast majority of its own aggregates, it does import a modest volume of crushed stone – on the order of 14 to 20 million metric tons per year in recent years (Mineral Commodity Summaries 2024). This is only about 1% of U.S. apparent consumption (over 1.5 billion tons), but imports play an outsized role in certain regions. Canada and Mexico are by far the largest suppliers, typically accounting for 70–80% of U.S. crushed stone import tonnage (Mineral Commodity Summaries 2024). From 2019–2022, about 47% of imported crushed stone came from Mexico and 31% from Canada (Mineral Commodity Summaries 2024). (Other notable sources include the Bahamas and Honduras (Mineral Commodity Summaries 2024).) In 2022, for example, the U.S. imported ~16 million tons of crushed stone (Mineral Commodity Summaries 2024); Mexican quarries supplied nearly half and Canadian quarries about one-third of that volume (Mineral Commodity Summaries 2024). By trade value, Canada has recently been the dominant source (about $170 million worth in 2023), with Mexico and Caribbean countries providing smaller shares (Gravel and Crushed Stone in United States | The Observatory of Economic Complexity).

Regionally, these imports flow into key states where local supply is constrained or expensive:

• Florida – Florida is one of the nation’s largest aggregate consumers (~140+ million tons/yr) but has limited high-quality limestone reserves outside one region. Historically about 5% of Florida’s aggregate demand has been met by “offshore” imports (from Mexico, Canada, the Bahamas) and another ~8% by rail from other U.S. states () (). South Florida in particular relies on seaborne shipments when local quarries can’t meet demand. For instance, Florida’s seaports handled roughly $600 million of imported cement and aggregate in 2024 to support a major state infrastructure initiative (Florida’s Seaports Are Leaders in Providing Critical Supply Chain Commodities Like Food, Fuel and Healthcare Supplies, While Also Serving as a Key Economic Engine, New Data Shows - Florida Ports Council). Mexican crushed limestone and Canadian granite have been important supplements for Florida’s roadbuilding and concrete markets. In the mid-2000s, Florida even received emergency aggregate shipments from Canada and the Bahamas when a court halted mining in its main quarry district (Lake Belt), underscoring the state’s import reliance.

• Texas – With its long land border, Texas is a key destination for Mexican aggregates. Quarries in northern Mexico regularly truck or rail crushed limestone across the border to Texas cities for cement and road base. In fact, during a 1992 trade case, it was noted that over half of all Mexican crushed limestone exports were consumed in Texas and nearby Gulf states (Texas Crushed Stone Co. v. U.S., 35 F.3d 1535 | Casetext Search + ...). Today, imports support fast-growing Texas metro areas and highway projects, especially in South Texas where domestic sources may be distant. Texas’s Gulf ports also receive aggregate by ship from Mexico’s Yucatán Peninsula and other sources. Any tariffs on Mexican stone would thus directly hit Texas’s construction supply chains.

• California – Coastal California has turned to imports as local sources face urbanization and environmental limits. A prominent example is Southern California’s use of Canadian aggregate: bulk carriers deliver sand and gravel from a Vancouver Island quarry (Polaris Materials’ Orca quarry in British Columbia) to the Port of Long Beach (Innovative Transport System Sails Aggregate Down the Pacific Coast – SWCPA). Each ship hauls up to 75,000 tons, which is unloaded and distributed to Los Angeles-area concrete plants (Innovative Transport System Sails Aggregate Down the Pacific Coast – SWCPA) (Innovative Transport System Sails Aggregate Down the Pacific Coast – SWCPA). This seaborne supply has proven economical – shipping a ton of rock ~1,450 miles by vessel costs only around $7, making Canadian aggregate competitive with trucking material from distant inland quarries in California (Innovative Transport System Sails Aggregate Down the Pacific Coast – SWCPA). Major cities like Los Angeles and San Francisco benefit from these imports to meet construction demand. Mexico has also been a source for California (e.g. sand from Baja California), though Canadian material currently dominates West Coast imports. Tariffs on Canadian or Mexican aggregates could raise costs for California’s import-dependent projects and force contractors to seek costlier local alternatives.

• New York & Great Lakes States – The Northeast and Great Lakes region also import aggregates from Canada. Great Lakes freighters carry about 5–6 million tons of Canadian limestone annually to U.S. ports on Lakes Superior, Huron, and Erie (How Great Lakes limestone shipments fared in 2023). For example, New York, Michigan, Ohio and others receive shipments from huge quarries in Ontario. In 2023, Canadian Great Lakes quarries shipped ~5.5 million tons of stone to the U.S., supplementing domestic production (How Great Lakes limestone shipments fared in 2023). Upstate New York and New England may also truck in specialty aggregate (like high-quality trap rock or granite) from Eastern Canada. Thus, while New York can source locally for many projects, certain large-scale jobs (bridges, road base) have leveraged Canadian imports. If trade frictions added tariffs, suppliers in these states could face higher costs on Canadian stone or have to haul rock from more distant U.S. quarries.

Overall, California, Florida, Texas, and New York exemplify states that rely on Canadian/Mexican aggregates to varying degrees due to geography and geology. These imported volumes are modest relative to total U.S. consumption, but they are critical in regions where demand outstrips local supply. Any change in tariff policy on North American aggregates would chiefly impact these hotspot states and their infrastructure projects.

Impacts of Tariffs on Prices and Supply Chains

Imposing tariffs on imported crushed stone would likely drive up costs for the U.S. construction industry and strain supply chains, especially in the affected regions. Aggregates are a heavy, low-margin commodity, so even a modest tariff adds noticeable cost per ton. For instance, a 25% duty on crushed stone (valued roughly $10–$15 per ton at the border) would add around $2–$4 per ton. That increment can significantly inflate prices in markets already paying high transport costs for imports. The price impact would be felt by asphalt, concrete, and road builders who use these aggregates daily. The NSSGA cautions that tariffs on aggregates would “raise costs across multiple industries,” ultimately burdening taxpayers and “reducing the miles of highways that can be built or expanded” on fixed budgets (). In other words, infrastructure dollars would not go as far if basic materials become pricier.

Historical evidence shows that even small supply constraints can lead to sharp price increases for aggregates. In 2007, a court-ordered shutdown of several Florida quarries (a scenario analogous to an import cut-off) caused local shortages. As a result, aggregate prices in parts of Florida’s market spiked to the “mid-$20s” per ton – roughly three times the typical U.S. average price at the time (~$7/ton) (NSDNR, MRB, Report ME 2008-2). This surge occurred because contractors suddenly had to truck and ship rock from much farther away. Likewise, during that crisis Florida actively sought overseas stone, and coastal aggregate prices rose about 9% nationwide in 2007 (NSDNR, MRB, Report ME 2008-2). A tariff could create a similar supply shock effect: imported tons might drop (or become more expensive), tightening supply in certain metros and allowing quarries to charge more. Areas like South Texas or South Florida, which depend on the marginal imported ton to meet demand, would see higher bids for aggregate, concrete, and roadwork contracts. State DOTs and project owners would either absorb the cost or scale back projects.

Supply-chain logistics would also adjust. Importers might reroute shipments or cut volume if tariffs erode their profit margin, leading to potential material shortages until alternatives are found. Domestic producers could see temporary demand spikes, but many cannot instantly increase output due to permit and capacity limits. Moreover, transporting domestic aggregate over longer distances (by rail or truck from other states) can be slow and expensive, potentially causing project delays. Industry experts warn that higher costs and material scarcity from tariffs would “strain federal, state and local funding for infrastructure,” forcing agencies to postpone or cancel some plans (). In sum, tariffs on Canadian/Mexican stone would ripple through the construction supply chain: contractors pay more for materials, some suppliers exit the market, and infrastructure construction could slow down due to budget pressures and logistical hurdles.

Historical Cases in the Aggregate Market

Historically, direct tariffs or trade restrictions on aggregates have been rare, precisely because these materials are vital and usually sourced domestically. One notable attempt occurred in 1992: U.S. producers filed an antidumping petition against crushed limestone imports from Mexico, alleging unfairly low-priced stone was harming the Texas Gulf Coast market. The U.S. International Trade Commission investigated, but ultimately made a negative injury determination (5–0), meaning no duties were imposed ([PDF] us court of international trade decisions reviewing determinations by ...). The case was dropped, and cross-border aggregate trade continued freely. This episode highlights that even 30 years ago, Mexican aggregate was significant enough to draw scrutiny, though trade officials recognized that penalizing it would not materially help (since domestic supply was limited in that region).

Aside from that case, aggregate imports have generally been treated as a necessity, not a target for protectionism. In fact, federal policy has often explicitly shielded aggregates from restrictive measures. For example, “Buy America” domestic sourcing rules for federal highway projects have historically exempted aggregates, recognizing that forcing 100% local rock sourcing would impede projects in areas that rely on imported stone (). This longstanding exclusion underscores the view that aggregates are strategically important and trade in them benefits U.S. infrastructure. NSSGA notes that Congress and the Federal Highway Administration deliberately kept aggregates out of domestic-only mandates to ensure continuity of supply (). In other words, lawmakers have been reluctant to let trade barriers disrupt the aggregate market.

That said, trade disputes involving related construction materials illustrate the possible consequences in the aggregate sector. A parallel example is the decades-long U.S.–Canada softwood lumber dispute, where tariffs on Canadian lumber repeatedly drove up U.S. homebuilding costs – a cautionary tale of protectionism backfiring in construction. Another parallel is cement imports: the U.S. imposed antidumping tariffs on Mexican cement from 1990 until 2006, which raised cement prices in border states and prompted shortages until a deal was struck (NSDNR, MRB, Report ME 2008-2) (this led Texas to rely on costlier domestic cement). Similarly, Mexico’s 2022 shutdown of a large U.S.-owned limestone quarry (Vulcan Materials in Quintana Roo) abruptly halted a major source of crushed stone for Gulf Coast markets, showing how non-tariff barriers can jolt supply. Florida and other states had to scramble for alternate supplies when that flow stopped. The lesson from these cases is that trade actions (tariffs, bans, or disputes) on basic building materials tend to have direct, inflationary impacts on downstream industries. When aggregates have been restricted – whether by policy or circumstance – the results have included spiking prices, project delays, and urgent efforts to find new sources. These historical precedents inform why the industry is strongly opposed to any new tariffs on aggregates.

Alternative Sourcing if Imports Are Disrupted

If tariffs or trade disputes curtailed aggregate imports from Canada and Mexico, the construction industry would pursue several alternative sourcing strategies to fill the gap:

• Increased U.S. Production: Domestic quarries would try to boost output, where possible, to replace lost imports. The U.S. has enormous aggregate resources nationally, so in theory production could expand. However, opening new pits or expanding mines is often difficult due to permitting, environmental regulations, and community opposition (the “Not In My Backyard” factor). Many high-demand urban areas (e.g. coastal California, New England) lack nearby aggregate deposits or face zoning hurdles, so simply producing more locally is not straightforward. Still, in the event of sustained tariffs, we might see renewed efforts to develop dormant quarry sites or expedite permits in states like Georgia, Alabama, or others with rock surplus. Interstate shipments would likely rise – for example, Georgia and Alabama already send crushed stone to Florida by rail (), and this could be scaled up further. Likewise, if Canadian stone to New York were cut off, quarries in states like Pennsylvania or Virginia might send more rock by train into the Northeast. The downside is higher transport cost and potential logistical bottlenecks (railcar shortages, truck driver constraints), which can only partially compensate for lost nearby imports.

• Other Import Sources: In lieu of Canada and Mexico, U.S. buyers could turn to alternate foreign suppliers not subject to the specific tariff or dispute. The global aggregate trade is relatively small, but certain countries in the Caribbean and beyond do export to the U.S. For example, the Bahamas, Jamaica, Honduras, and Norway have supplied crushed stone to U.S. markets (Gravel and Crushed Stone in United States | The Observatory of Economic Complexity) (Gravel and Crushed Stone in United States | The Observatory of Economic Complexity). In recent years when Mexican supply dipped, Honduras and Jamaica substantially increased their sales to the U.S. (Gravel and Crushed Stone in United States | The Observatory of Economic Complexity). These nations have large limestone quarries and cheap water transport to Florida and Gulf Coast ports. If Canadian and Mexican material became pricier, importers could shift orders to Caribbean producers (many of whom enjoy duty-free access under other trade arrangements or normal MFN, since U.S. tariffs on aggregates are zero for all countries). However, the volumes from these smaller countries might not fully replace Canada/Mexico’s supply in the short run. Shipping from more distant sources (e.g. crushed granite from South America or Europe) is also possible; bulk freight rates are low, but longer voyages add cost and time. Still, we might see creative sourcing – for instance, a Norwegian granite shipment arrived in late 2024 (Gravel and Crushed Stone in United States | The Observatory of Economic Complexity) (Gravel and Crushed Stone in United States | The Observatory of Economic Complexity), and countries like Turkey or Mexico’s non-tariffed neighbors could step up exports if economically viable. The U.S. could even import specialty aggregates from as far as Asia for high-value uses (though unlikely for general bulk needs). In summary, diversifying import origins would be a key workaround, leveraging the fact that many other countries have ample stone and would be eager to supply a constrained U.S. market if tariffs hit North American sources.

• Substitute Materials: Another buffer is using alternative materials or recycled aggregates in place of imported crushed stone. For certain applications, natural sand and gravel can substitute for crushed rock – e.g. local sand/gravel might be used in concrete mixes if crushed limestone is too costly. (The U.S. has significant sand & gravel operations in many states, though quality and availability vary.) Additionally, industrial by-products can stand in as aggregate: iron and steel slag from steel mills is often used as a road base or asphalt aggregate, and could take a larger role if virgin stone supplies tighten (Mineral Commodity Summaries 2024). Some lightweight substitutes like expanded shale, clay, or recycled concrete are also options for non-structural fill or lower-tier aggregate needs (Mineral Commodity Summaries 2024). Recycling old concrete and asphalt is an especially growing practice – reclaimed asphalt pavement and crushed concrete can be reused in new pavements, reducing the need for fresh aggregate (Mineral Commodity Summaries 2024). Currently, recycled materials are a small fraction of total aggregate use (Mineral Commodity Summaries 2024), but higher prices (from tariffs) would make recycling more economically attractive. Construction firms might invest more in crushing and reusing demolition debris if imported stone costs soar. These substitutes come with limitations (for high-strength concrete, you still need quality aggregate), but they can alleviate demand for new crushed stone at the margins.

• Project Adjustments: In extreme cases, if imports were severely disrupted and alternatives couldn’t fully cover the shortfall, project planners might adjust designs or schedules. For example, highway engineers could opt for thinner layers or different pavement designs that use less aggregate, or choose smaller, phased projects that require fewer materials at once. Non-critical projects might be deferred until material supply normalizes. While not a true “source,” such measures are a last resort to cope with scarcity – essentially stretching the available aggregate further.

In practice, the industry would likely deploy a combination of these responses. A tariff-induced supply crunch would first tap other countries’ supply (due to the immediacy of need), while over the medium term domestic production and recycling could ramp up. The aggregate sector is adaptable but only to a point – geography and geology dictate where materials come from. Thus, maintaining multiple supply channels (domestic quarries, imports from various nations, recycled outputs) is key to resilience. This is one reason industry leaders want to keep North American trade flows open; it’s easier to source affordably from your neighbor than to activate complicated contingency sources.

Outlook for Trade Policy, Construction Costs & Infrastructure

The prospect of tariffs on Canadian and Mexican aggregates raises important questions about future trade policy and U.S. infrastructure goals. On one hand, the recent USMCA agreement and longstanding trade ties have ensured a stable, duty-free supply of construction materials across North America – a trend likely to continue if economic integration remains a priority. Imposing new tariffs on such a fundamental input would counteract current efforts to upgrade infrastructure. In fact, the timing is critical: the U.S. has launched major federal infrastructure investments (e.g. highway upgrades, public works funded by the Infrastructure Investment and Jobs Act), and those projects count on affordable aggregates. A sudden cost increase from tariffs would force governments to either seek more funding or scale back plans. Policymakers are aware of this: trade experts note that broad tariffs on Canada/Mexico would “cause prices to rise” and drag on economic growth (Trump's 25% tariffs on Canada and Mexico will be a blow to all 3 ...), and specifically, higher material costs could undermine infrastructure modernization. Therefore, future trade policy may be careful to avoid hampering construction inputs. We may see explicit carve-outs or exemptions for critical materials (like aggregates) in any aggressive trade measures. The NSSGA’s advocacy in early 2025 – urging an aggregates exemption in potential Canada/Mexico tariffs () – aligns with a broader push to keep essential supply chains intact even amid trade disputes.

If, however, tariffs do come into play (for instance, as a negotiating tactic or in retaliation cycles), the long-term effect could be to incentivize greater self-reliance and supply chain shifts. The U.S. might invest more in developing local aggregate sources or improving rail/barge logistics to haul stone from where it’s abundant to where it’s needed. We could also see more regional stockpiling of aggregates as a buffer against trade disruptions – akin to strategic reserves for critical commodities. Additionally, such a scenario would likely accelerate technological and market shifts: higher costs for imported stone might spur innovations in recycling, material efficiency, or the use of alternative aggregates on a wider scale, permanently changing how the industry operates. Construction firms might lock in long-term contracts with a variety of suppliers (domestic and foreign) to diversify risk. From Canada’s and Mexico’s perspective, any U.S. tariffs on aggregates (or related building materials) could prompt them to seek other export markets or retaliate on U.S. goods, which could further influence future trade negotiations.

In terms of infrastructure development, maintaining a smooth flow of aggregates is crucial for meeting construction timelines and budgets. If trade barriers disrupted that flow, infrastructure projects could face delays and cost overruns, which in turn might dampen political support for aggressive trade measures. Thus, one likely outcome is that economic reality will shape trade policy: recognizing that basic inputs like crushed stone underpin the entire construction sector, U.S. leaders may prioritize keeping these materials accessible and affordable. In the near future, this could translate into trade policy that balances tough negotiating stances with practical exemptions for things like aggregates, similar to how energy products have sometimes been spared higher tariffs (President Trump Imposes 25% Tariffs on Canada and Mexico, and 10% Tariffs on China | White & Case LLP).

Overall, the intersection of tariffs and construction aggregates highlights an important point: trade decisions are intimately linked to domestic economic outcomes. Should tariffs on Canadian and Mexican crushed stone ever materialize, Americans could see higher construction costs, slower infrastructure build-out, and pressure on supply chains – outcomes at odds with the current drive to rebuild roads, bridges, and housing cost-effectively. Conversely, preserving free trade for these low-cost, high-volume inputs will help stabilize prices and ensure that ambitious infrastructure programs can proceed on schedule. The future likely holds a continued emphasis on supply stability – whether through trade agreements, industry adaptability, or both – so that roads get built, homes get constructed, and the economy isn’t bogged down by the cost of the very rocks beneath its foundations.

Sources: Recent U.S. Geological Survey data on crushed stone imports and tariffs (Mineral Commodity Summaries 2024) (Mineral Commodity Summaries 2024); industry communications from NSSGA () (); trade analyses and news on proposed tariffs (President Trump Imposes 25% Tariffs on Canada and Mexico, and 10% Tariffs on China | White & Case LLP) (President Trump Threatens Tariffs on All Goods Imported from Mexico to Address “Border Crisis” | White & Case LLP); and historical case studies of aggregate supply and pricing (NSDNR, MRB, Report ME 2008-2) ([PDF] us court of international trade decisions reviewing determinations by ...)