| 3420 | Library binder manufacturing | |
| 3320 | Library bookcase manufacturing | |
| 3320 | Library furniture manufacturing | |
| 9420 | Library not connected with educational institution | |
| 3819 | License number plate manufacturing | |
| 3119 | Licorice candy manufacturing | |
| 3212 | Life belt, excluding cork, manufacturing | |
| 8200 | Life insurance underwriting or selling | |
| 3212 | Life jacket manufacturing | |
| 3212 | Life preserver, excluding cork, manufacturing | |
| 3559 | Life preserver, inflatable, rubber | |
| 3559 | Life raft, rubber | |
| 9320 | Life sciences research institute | |
| 3841 | Lifeboat building and repairing | |
| 3811 | Lifting jack, except hydraulic, manufacturing | |
| 3511 | Light acid manufacturing | |
| 3699 | Lighter flint manufacturing | |
| 3901 | Lighter, cigarette, precious metal | |
| 3841 | Lighter, marine, building and repairing | |
| 7123 | Lighterage service | |
| 5000 | Lighthouse construction | |
| 7123 | Lighthouse operation | |
| 7123 | Lighthouse service | |
| 3839 | Lighting fixture manufacturing | |
| 6200 | Lighting fixture, electric, retailing | |
| 6100 | Lighting fixture, electric, wholesaling | |
| 3620 | Lighting glassware, blowing and pressing | |
| 5000 | Lighting system installation | |
| 5000 | Lighting system repairing | |
| 3839 | Lightning arrester or coil manufacturing | |
| 3819 | Lightning rod manufacturing | |
| 3513 | Lignin plastic manufacturing | |
| 3540 | Lignite briquette manufacturing, not at mine | |
| 2100 | Lignite mining | |
| 3692 | Like kiln operation | |
| 3211 | Liking fabric manufacturing | |
| 3829 | Limber, gun and caisson manufacturing | |
| 3529 | Lime bleach manufacturing | |
| 3699 | Lime brick manufacturing | |
| 3699 | Lime rock grinding and treating, not at mine, pit or quarry | |