Metal and non-metal mines where MSHA measured a miner over a limit
MSHA has taken 39,676 personal air samples at US metal and non-metal mines since 2023. 12,419 of them were for a contaminant with an applicable exposure limit, and 1,329 came back over it, or 10.7%%, across 621 mines in 49 states. Respirable quartz is the most common exceedance, diesel particulate the second.
Quarries, sand and gravel pits, cement plants and metal mines, by state, by contaminant and by the job the miner was doing. This is the half of the federal health record the coal programmes cannot see: MSHA measures silica in coal dust and noise almost entirely at coal mines, and samples everything else, from respirable quartz to diesel exhaust to lead, through a separate metal and non-metal file.
Three things worth knowing before reading a number here. A figure is a multiple of the limit for the contaminant sampled, so 2.0 is twice the limit for that substance; each contaminant carries its own limit in its own unit, and the ratio is the only figure that compares a quartz reading to a diesel one. Roughly two samples in three are for a contaminant with no applicable limit, which is a screening measurement rather than a pass, so every share below is taken over limit-tested samples only. And a sample over a limit is an exposure measurement, not a violation finding.
Looking at coal instead? See coal mines ranked by silica in their dust samples or mines with noise samples over the legal limit. For enforcement, see mines ranked by MSHA violations.
MSHA took 39,676 personal air samples at 8,207 metal and non-metal operations in this window. 12,419 were for a contaminant with an applicable exposure limit, and 1,329 of those came back over it.
| Contaminant | Samples over the limit | Limit-tested | Share over | Mines | Worst |
|---|---|---|---|---|---|
| Quartz, respirable, >1% Qtz |
897
|
6,181 | 14.5% | 475 | 16.2x |
| Nuisance dust, total, <1% Qtz |
228
|
1,618 | 14.1% | 88 | 30.2x |
| Diesel particulate (total carbon) |
144
|
1,488 | 9.7% | 56 | 5.8x |
| Nuisance dust, respirable, <1% Qtz |
27
|
1,947 | 1.4% | 22 | 69.8x |
| Lead, inorganic dust |
14
|
162 | 8.6% | 3 | 7.9x |
| Calcium oxide |
9
|
211 | 4.3% | 8 | 2.7x |
| Cristobalite, respirable |
5
|
10 | 50.0% | 1 | 3.6x |
| Mixed Silica |
5
|
8 | 62.5% | 1 | 3.9x |
| Aluminum oxide dust |
2
|
5 | 40.0% | 1 | 2.1x |
| Lead fumes |
1
|
185 | 0.5% | 1 | 1.7x |
| Iron oxide fumes |
1
|
169 | 0.6% | 1 | 1.1x |
| Beryllium dust |
1
|
123 | 0.8% | 1 | 1.0x |
Contaminant labels are MSHA’s own, with one exception stated plainly: the agency publishes a diesel sample as up to three separate carbon readings of the same cassette, and only the total-carbon basis is counted here, renamed to diesel particulate. Counts can sum above the national total, because one metal panel screens a single sample for as many as eight substances and can be over on two of them.
Mines where MSHA measured a miner over a permissible exposure limit since 2023-01-01. The worst column is a multiple of the limit for whichever contaminant it was, so 3.0 is three times that limit.
| State | Mines over a limit | Samples over | Limit-tested | Share over | Worst | Buy the named roster |
|---|---|---|---|---|---|---|
| PA |
52
|
81 | 881 | 9.2% | 23.0x | |
| MO |
42
|
123 | 866 | 14.2% | 18.4x | |
| UT |
30
|
43 | 370 | 11.6% | 5.3x | |
| NY |
27
|
69 | 546 | 12.6% | 13.1x | |
| TX |
27
|
42 | 429 | 9.8% | 4.1x | |
| OK |
25
|
35 | 266 | 13.2% | 5.3x | |
| AZ |
24
|
85 | 348 | 24.4% | 10.1x | |
| MN |
22
|
40 | 297 | 13.5% | 8.4x | |
| OH |
21
|
35 | 499 | 7.0% | 3.5x | |
| WY |
21
|
71 | 324 | 21.9% | 4.6x | |
| KY |
20
|
29 | 600 | 4.8% | 41.9x | |
| TN |
20
|
46 | 494 | 9.3% | 3.7x | |
| CO |
19
|
40 | 419 | 9.5% | 5.6x | |
| ID |
18
|
51 | 201 | 25.4% | 30.2x | |
| NC |
17
|
29 | 456 | 6.4% | 3.6x | |
| NV |
17
|
58 | 315 | 18.4% | 4.1x | |
| AR |
16
|
46 | 268 | 17.2% | 16.2x | |
| WV |
15
|
30 | 348 | 8.6% | 3.8x | |
| VA |
12
|
22 | 416 | 5.3% | 19.8x | |
| AL |
11
|
16 | 154 | 10.4% | 69.8x | |
| IL |
11
|
18 | 261 | 6.9% | 2.5x | |
| MT |
11
|
17 | 172 | 9.9% | 3.8x | |
| NM |
11
|
19 | 127 | 15.0% | 18.1x | |
| CA |
10
|
13 | 222 | 5.9% | 3.8x | |
| MA |
10
|
19 | 106 | 17.9% | 5.2x | |
| MI |
10
|
24 | 229 | 10.5% | 11.3x | |
| IA |
9
|
20 | 259 | 7.7% | 3.0x | |
| WI |
9
|
14 | 197 | 7.1% | 1.6x | |
| GA |
8
|
9 | 331 | 2.7% | 3.2x | |
| IN |
8
|
23 | 287 | 8.0% | 18.4x | |
| KS |
7
|
10 | 174 | 5.7% | 2.9x | |
| FL |
6
|
13 | 126 | 10.3% | 4.4x | |
| AK |
5
|
16 | 107 | 15.0% | 7.9x | |
| CT |
5
|
14 | 62 | 22.6% | 3.9x | |
| SC |
5
|
15 | 177 | 8.5% | 2.7x | |
| SD |
5
|
10 | 108 | 9.3% | 2.7x | |
| VT |
5
|
13 | 135 | 9.6% | 3.2x | |
| WA |
5
|
7 | 82 | 8.5% | 3.4x | |
| MD |
4
|
6 | 107 | 5.6% | 6.0x | too thin to sell |
| MS |
4
|
7 | 57 | 12.3% | 2.8x | too thin to sell |
| NE |
4
|
22 | 102 | 21.6% | 13.5x | too thin to sell |
| LA |
3
|
3 | 54 | 5.6% | 3.6x | too thin to sell |
| ME |
2
|
6 | 42 | 14.3% | 3.3x | too thin to sell |
| NJ |
2
|
8 | 63 | 12.7% | 2.7x | too thin to sell |
| PR |
2
|
6 | 136 | 4.4% | 2.1x | too thin to sell |
| ND |
1
|
3 | 45 | 6.7% | 2.5x | too thin to sell |
| NH |
1
|
1 | 30 | 3.3% | 1.1x | too thin to sell |
| OR |
1
|
1 | 79 | 1.3% | 1.5x | too thin to sell |
| RI |
1
|
1 | 23 | 4.3% | 1.0x | too thin to sell |
The named roster for a state lists every mine over a limit ranked worst first, with the operator of record, what its miners were over on, how far over, the date it was last over, the site’s headcount, and the occupations driving it. Where a different company held a mine while it was being sampled, that company is named too. Figures are MSHA’s own published sample results, so anything in the roster can be checked against the agency’s file.
| Occupation | Samples over | Limit-tested | Share over |
|---|---|---|---|
| Crusher Oper/Worker | 177 | 1,381 | 12.8% |
| Laborer, Bullgang | 146 | 1,137 | 12.8% |
| Utility Man | 143 | 1,206 | 11.9% |
| Bagging Operator | 134 | 694 | 19.3% |
| Cleanup Man | 69 | 467 | 14.8% |
| Stone Polisher/Cutter | 63 | 311 | 20.3% |
| Front-end Loader Operator | 52 | 1,406 | 3.7% |
| Dry Screen Plant Operator | 44 | 324 | 13.6% |
| Truck Driver | 43 | 919 | 4.7% |
| Blaster, Powder Gang | 37 | 212 | 17.5% |
| Mechanic | 35 | 395 | 8.9% |
| Kiln/Dryer Operator | 27 | 214 | 12.6% |
| Scaling (mechanical) | 24 | 269 | 8.9% |
| Ball Mill Operator | 22 | 115 | 19.1% |
| Drill Operator, Rotary | 21 | 278 | 7.6% |
| Bobcat Operator | 21 | 105 | 20.0% |
| Mucking Mach. Operator | 20 | 102 | 19.6% |
| Lab Technician | 19 | 157 | 12.1% |
| Roof Bolter, Rock | 19 | 146 | 13.0% |
| Drill Operator, Jumbo Perc. | 15 | 106 | 14.2% |
| Cutting Mach Operator | 13 | 69 | 18.8% |
| Flotation/Concentrator Oper. | 13 | 92 | 14.1% |
| Supervisor, Co. Official | 12 | 163 | 7.4% |
| Cont. Miner Operator | 12 | 57 | 21.1% |
| Truck Loader | 11 | 79 | 13.9% |
| Building Repair/Maint. | 10 | 103 | 9.7% |
| Belt Crew | 10 | 47 | 21.3% |
| Forklift Operator | 8 | 129 | 6.2% |
| Packaging Operations Worker | 8 | 59 | 13.6% |
| Rotary Bucket Ex. Operator | 6 | 158 | 3.8% |
| Bulldozer Operator | 5 | 102 | 4.9% |
| Scale Man | 5 | 30 | 16.7% |
| Drill Operator, Rotary Air | 5 | 63 | 7.9% |
| Pipe Fitter/Millright/Plumber | 5 | 47 | 10.6% |
| Pelletizer Operator | 5 | 26 | 19.2% |
| Shuttle Car Operator (diesel) | 5 | 21 | 23.8% |
| Screen/Scalper Operator | 4 | 32 | 12.5% |
| Oiler, Greaser | 4 | 38 | 10.5% |
| Roof Bolter, Mounted | 4 | 56 | 7.1% |
| Washer Operator | 3 | 75 | 4.0% |
| Jackhammer Operator | 3 | 20 | 15.0% |
| Dump Operator | 3 | 11 | 27.3% |
| Scaling (hand) | 3 | 25 | 12.0% |
| Overhead Crane Operator | 3 | 6 | 50.0% |
| Motorman | 3 | 11 | 27.3% |
| Mason | 3 | 6 | 50.0% |
| Backhoe Operator | 2 | 132 | 1.5% |
| Complete Load-Haul-Dump | 2 | 55 | 3.6% |
| Scraper Operator | 2 | 24 | 8.3% |
| Tractor Operator | 2 | 31 | 6.5% |
| Miner, Drift | 2 | 19 | 10.5% |
| Hammer Mill Operator | 2 | 20 | 10.0% |
| Belt Cleaner | 2 | 15 | 13.3% |
| Shotcrete/Gunite Man | 2 | 13 | 15.4% |
| Cutting Mach Helper | 2 | 6 | 33.3% |
| Shovel Operator | 1 | 38 | 2.6% |
| Hydrating Plant Operator | 1 | 41 | 2.4% |
| Diamond Drill Operator | 1 | 16 | 6.3% |
| Sampler, Dust | 1 | 12 | 8.3% |
| Drill Oper., Jackleg/Stoper | 1 | 20 | 5.0% |
| Iron Worker | 1 | 12 | 8.3% |
| Warehouse Man | 1 | 8 | 12.5% |
| Drill Helper | 1 | 8 | 12.5% |
| Mobile Crane Operator | 1 | 3 | 33.3% |
| Nipper, Supply Man | 1 | 9 | 11.1% |
| Cont. Miner Helper | 1 | 7 | 14.3% |
| Ram Car Operator | 1 | 5 | 20.0% |
| Drill Operator, Jet Piercing | 1 | 5 | 20.0% |
| Cement/Concrete Man | 1 | 2 | 50.0% |
Occupation labels are MSHA’s own job codes, unedited. A job that appears rarely can show an extreme share off a handful of samples, so read the share beside the limit-tested count. Occupation is the level at which a control actually gets specified, which is why it is here rather than in a footnote.