4.3 LP gas, diesel and carbon monoxide

1 Fuel storage: what the standard incorporates

1910.178(f)(1) requires the storage and handling of liquid fuels such as gasoline and diesel to be in accordance with the NFPA Flammable and Combustible Liquids Code, NFPA 30, incorporated by reference in 1910.6. 1910.178(f)(2) does the same for liquefied petroleum gas fuel, referencing NFPA 58, Storage and Handling of Liquefied Petroleum Gases.

Those two NFPA documents are copyrighted standards published and sold by the National Fire Protection Association. This course names them, as the CFR does, and does not reproduce them. What matters at operator level is that fuel storage on your site is governed by a specific published code, not by convention — and that your employer is responsible for the storage arrangements you refuel from.

2 Refueling: five sentences worth memorizing

Paragraph (p) of 1910.178 is short and its fuel rules are absolute.

(p)(4) is the one operators talk themselves out of. A smell of LP gas, a wet patch under a diesel truck or a fitting that hisses is a leak, and the standard's answer is that the truck does not operate until it is corrected. There is no "finish the pallets first" in the text.

3 Changing an LP cylinder

LP changeovers happen several times a shift on a busy fleet, which is what makes them easy to do badly. The sequence below follows the standard's rules plus the practices that keep the liquid where it belongs.

1. 1
   Park outdoors or in the designated area, forks down, controls neutralized, brake set — the parking rule of 1910.178(m)(5)(i).
2. 2
   Close the service valve and run the engine until it stops, where your site's procedure calls for it, so the fuel line is empty before you break the connection.
3. 3
   Shut the engine off entirely, and no smoking or ignition sources anywhere near the changeover.
4. 4
   Wear gloves and eye protection. Liquid LP escaping from a fitting causes an immediate cold burn.
5. 5
   Disconnect, lift with your legs, and use a cart or a hoist for the change if the cylinder is heavy — an LP cylinder is an awkward, dense load.
6. 6
   Seat the new cylinder on its locating pin so the pressure relief valve is oriented as the manufacturer requires, secure the strap, connect, then open the valve slowly and check for leaks by smell and sound before starting.

4 Carbon monoxide

1910.178(l)(3)(ii)(H) makes closed environments and other areas where insufficient ventilation or poor vehicle maintenance could cause a buildup of carbon monoxide or diesel exhaust a required training topic. That paragraph names both causes, and the second one is the one people forget: a badly tuned engine can put out many times the CO of a healthy one.

Carbon monoxide is colorless and odorless, it binds to hemoglobin far more readily than oxygen does, and its early symptoms — headache, dizziness, nausea, fatigue, confusion — are exactly the symptoms a worker attributes to a long shift. By the time someone realizes what is happening, judgement is already impaired.

The situations that concentrate it are predictable: working inside a trailer or shipping container, a cold store or freezer with the doors closed, a building whose ventilation is shut down for winter, an enclosed loading bay, and any indoor space where propane or diesel trucks run continuously. Where employees are exposed, the exposure limits of 1910.1000 apply, and monitoring is your employer's responsibility.

• Ventilate before it is a problem, not after someone feels unwell.
• Take symptoms seriously in yourself and others — headache and dizziness in a warehouse with engine trucks is not "just tired."
• Get to fresh air first, then report. Do not investigate the source yourself.
• Report a truck that smells wrong or runs rough. Poor maintenance is named in the standard as a cause.
• Prefer electric trucks for enclosed work where the fleet allows it — this is the fleet decision that removes the hazard instead of controlling it.

5 Diesel exhaust and dust

Diesel exhaust carries fine particulate as well as carbon monoxide, and enclosed operation concentrates both. Where diesel trucks work indoors, the controls are the same family as for CO: ventilation, engine maintenance, and limiting the time and number of engine trucks in the space.

1910.178(q)(8) is directly relevant here and often overlooked. Water mufflers shall be filled daily, or as frequently as necessary to prevent the water dropping below 75 percent of filled capacity; vehicles with mufflers having screens or other parts that may become clogged shall not be operated while those parts are clogged; and any vehicle that emits hazardous sparks or flames from the exhaust system shall immediately be removed from service and not returned until the cause has been eliminated or corrected.

1910.178(q)(9) adds the temperature rule from Chapter 1 of this part: a truck running hotter than its normal operating temperature in a way that creates a hazardous condition comes out of service until the cause is fixed.

6 The fire triangle in a fuel area

Everything in this chapter is an attempt to keep fuel and an ignition source apart. Put the two lists side by side and the rules stop being arbitrary.