Radioactive Material Labeling Basics: WHITE-I, YELLOW-II, YELLOW-III

Why Labels Matter

Radioactive material labels serve two critical purposes: they communicate the hazard level to package handlers during normal operations, and they provide essential information to emergency responders in case of an accident. The label category (WHITE-I, YELLOW-II, or YELLOW-III) instantly tells anyone handling the package how much radiation it emits and how carefully it needs to be handled.

I've seen carriers refuse shipments because the TI on the label didn't match the shipping papers. It was a simple transcription error—the shipper wrote “0.3” on the label but “0.8” on the paperwork. The carrier caught it during their acceptance check, and the shipment sat in the dock until someone could drive back to fix it. A small mistake, but it cost half a day and a lot of frustration.

Using the wrong label isn't just a paperwork violation—it can lead to improper handling, exceeded dose limits for workers, or incorrect vehicle loading. Carriers use the Transport Index printed on labels to determine how many packages can be loaded in a single vehicle and how far they must be kept from passengers.

Who Needs to Know This

This applies to anyone who:

• Prepares radioactive material packages for shipment
• Applies labels to RAM packages
• Receives and inspects incoming radioactive shipments
• Handles or transports labeled packages
• Responds to transportation incidents involving RAM

The Three Radioactive Labels

The DOT specifies three radioactive material labels, each indicating a different hazard level. The requirements are found in 49 CFR 172.403 and 49 CFR 172.436-440.

RADIOACTIVE WHITE-I

The WHITE-I label indicates the lowest hazard level. It's all white with a single red bar at the bottom.

Requirements to use WHITE-I:

• Transport Index (TI) must be 0 (zero)
• Surface dose rate must not exceed 0.5 mrem/hr (0.005 mSv/hr)

WHITE-I packages have essentially no radiation exposure concern at the package surface. These are typically very low activity shipments or well-shielded sources.

RADIOACTIVE YELLOW-II

The YELLOW-II label indicates a moderate hazard level. The upper half is yellow with two red bars at the bottom.

Requirements to use YELLOW-II:

• Transport Index must be greater than 0 but not exceed 1.0
• Surface dose rate must not exceed 50 mrem/hr (0.5 mSv/hr)

YELLOW-II packages have measurable radiation at 1 meter but at relatively low levels. Handlers should minimize time near the package but no special handling restrictions apply beyond standard practices.

Most medical isotope shipments fall into YELLOW-II territory. Tc-99m generators, I-131 therapy doses, and diagnostic radiopharmaceuticals typically have enough activity to register a measurable TI but stay well under 1.0. If you're shipping medical isotopes regularly, YELLOW-II will probably be your most common label.

RADIOACTIVE YELLOW-III

The YELLOW-III label indicates the highest hazard level that can be shipped without special arrangements. The upper half is yellow with three red bars at the bottom.

Requirements for YELLOW-III:

• Transport Index greater than 1.0 but not exceeding 10
• OR surface dose rate greater than 50 mrem/hr but not exceeding 200 mrem/hr (2 mSv/hr)

The most common mistake I see is forgetting that both conditions must be checked. A shipper measures 0.8 mrem/hr at 1 meter, calculates TI = 0.8, and slaps on a YELLOW-II label without ever measuring the surface dose rate. If the surface happens to be 55 mrem/hr, that package actually needs YELLOW-III. Always check both values—the label category is determined by whichever one pushes you into the higher category.

Label Selection Summary

Understanding Transport Index (TI)

The Transport Index is the maximum radiation level in mrem/hr at 1 meter from any external surface of the package. It's defined in 49 CFR 173.403.

How TI is Determined

• Measure the dose rate at 1 meter from the package surface on all sides
• Take the highest reading
• Round up to the nearest tenth (0.1)
• Exception: if the measured value is 0.05 or less, the TI is 0

For example:

• Measured 0.03 mrem/hr at 1 meter → TI = 0 (WHITE-I eligible)
• Measured 0.06 mrem/hr at 1 meter → TI = 0.1 (YELLOW-II)
• Measured 0.95 mrem/hr at 1 meter → TI = 1.0 (YELLOW-II)
• Measured 1.01 mrem/hr at 1 meter → TI = 1.1 (YELLOW-III)

If you don't have access to a calibrated survey meter, you can often calculate the expected dose rate using the source activity, the gamma constant for your nuclide, and the shielding factors. LabelCalc can help with this. But for regulatory compliance, you should still verify with an actual measurement before shipment—calculations are estimates, and carriers may ask for survey documentation.

Surface Dose Rate Limits

In addition to TI, you must measure the dose rate at the package surface. The maximum surface dose rate determines both the label category and whether the package can be shipped at all.

I once worked with a facility that needed to ship a high-activity industrial source. The surface dose rate measured 180 mrem/hr—just under the 200 mrem/hr limit for normal shipment. We could have shipped it as YELLOW-III, but the margins were tight. Instead, we added additional shielding to bring it down to 120 mrem/hr. The extra shielding cost a few hundred dollars, but it gave us comfortable margin and avoided any risk of the package being rejected if the carrier's survey meter read slightly higher than ours.

Label Placement Requirements

Proper label placement is specified in 49 CFR 172.406:

• Two labels required on opposite sides of the package
• Labels must be placed on the same surface as the proper shipping name and UN number
• Labels must be visible from the direction they face
• Labels must not be obscured by markings or attachments
• Labels must be durable and weather-resistant

How RadShip.com Helps

RadShip.com simplifies label determination by:

• LabelCalc – Enter your surface dose rate and dose rate at 1 meter, and it automatically determines the correct label category and TI.
• RAMcalc – Integrates with package type determination so you know the full picture: package type, label category, and shipping requirements.
• Automatic TI rounding according to regulatory requirements.

Label determination seems simple—just compare two numbers to a table. But when you're shipping regularly, small errors add up. I've seen shippers accidentally round TI the wrong direction, forget to check surface dose rate, or simply grab the wrong label from the drawer. An automated tool eliminates these mistakes and creates a consistent record of how each label was determined. When an inspector asks why you chose YELLOW-II instead of YELLOW-III, you have documentation showing exactly what values were used.

Or skip the manual work and use LabelCalc to handle label determination automatically. Try it free for 7 days.

Common Questions

What if I don't have a radiation meter?

You need one. You cannot legally ship radioactive material without verifying the dose rates. If you don't have a calibrated survey meter, you must either acquire one or have your radiation safety officer perform the measurements.

Can I use a higher label category than required?

Yes, but don't. While using YELLOW-III on a WHITE-I package won't cause a safety problem, it creates unnecessary handling restrictions and paperwork. Use the correct label for your measured values.

Do I need to measure every package?

Generally, yes. However, if you routinely ship identical packages (same source, same shielding, same configuration), you may be able to establish representative measurements. Document your basis carefully.

What about fissile material labels?

Fissile packages need an additional label. If your package contains fissile material (U-233, U-235, Pu-239, Pu-241), you'll need a FISSILE label in addition to the appropriate radioactive label, showing the Criticality Safety Index (CSI).

The most important thing to understand is that labels exist to protect people, not just to satisfy regulators. A handler who sees YELLOW-III knows to minimize time near that package. A driver knows how many YELLOW-III packages can go in one vehicle. Emergency responders know what level of hazard they're dealing with. When you apply the correct label, you're giving everyone in the shipping chain the information they need to handle your package safely.

Summary: Your Labeling Checklist

Before applying labels, ensure:

• ☐ You've confirmed the package is not excepted (excepted packages don't require labels)
• ☐ You've measured the dose rate at the package surface
• ☐ You've measured the dose rate at 1 meter from the package surface
• ☐ You've calculated the Transport Index (rounded up to nearest 0.1)
• ☐ You've selected the correct label based on both TI and surface dose rate
• ☐ You've filled in the TI on the label
• ☐ You've placed two labels on opposite sides of the package

Or skip the manual work and use LabelCalc to determine your label category automatically.

Regulatory References

DOT Requirements:

• 49 CFR 172.403 – Radioactive materials labeling requirements
• 49 CFR 172.406 – Placement of labels
• 49 CFR 172.436 – RADIOACTIVE WHITE-I label
• 49 CFR 172.438 – RADIOACTIVE YELLOW-II label
• 49 CFR 172.440 – RADIOACTIVE YELLOW-III label
• 49 CFR 173.403 – Definitions (Transport Index)
• 49 CFR 173.441 – Radiation level limitations

IATA (Air Transport):

• IATA Dangerous Goods Regulations, Section 10.7 – Labeling requirements