The EPA – and most states with an authorized hazardous waste program – identify two types of hazardous waste:

Listed:

• Hazardous waste from non-specific sources (F-codes).
• Hazardous waste from specific sources (K-codes).
• Discarded commercial chemical products, off-specification species, container residues, and spill residues thereof (P-codes & U-codes).

And…

Characteristic:

• Ignitability (D001)
• Corrosivity (D002)
• Reactivity (D003)
• Toxicity (D004 – D043)

The purpose of this article is to explain how EPA identifies the characteristic of Reactivity (D003).

The characteristic of Reactivity is codified in Title 40 of the Code of Federal Regulations at 40 CFR 261.23.  It reads:

a) A solid waste exhibits the characteristic of reactivity if a representative sample of the waste has any of the following properties:

(1) It is normally unstable and readily undergoes violent change without detonating.

(2) It reacts violently with water.

(3) It forms potentially explosive mixtures with water.

(4) When mixed with water, it generates toxic gases, vapors or fumes in a quantity sufficient to present a danger to human health or the environment.

(5) It is a cyanide or sulfide bearing waste which, when exposed to pH conditions between 2 and 12.5, can generate toxic gases, vapors or fumes in a quantity sufficient to present a danger to human health or the environment.

(6) It is capable of detonation or explosive reaction if it is subjected to a strong initiating source or if heated under confinement.

(7) It is readily capable of detonation or explosive decomposition or reaction at standard temperature and pressure.

(8) It is a forbidden explosive as defined in 49 CFR 173.54, or is a Division 1.1, 1.2 or 1.3 explosive as defined in 49 CFR 173.50 and 173.53.

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(b) A solid waste that exhibits the characteristic of reactivity has the EPA Hazardous Waste Number of D003.

Right from the start – paragraph (a) – the regulation may mislead you into thinking there is a test method for Reactivity because of its reference to “a representative sample of the waste…”.  There is not.  Nowhere in section §261.23 does it refer to a test method for determining the characteristic of Reactivity.  For the characteristic of Reactivity a generator making a hazardous waste determination must rely solely on generator knowledge as allowed by §261.10(a)(2)(ii).

From the EPA website:  "There are currently no test methods available."

So what is a reactive hazardous waste?  It is any solid waste (i.e. any material that is disposed of by being abandoned or recycled, is inherently waste-like, or is a military munition) that exhibits any one of the following characteristics:

Unstable:

It is normally unstable and readily undergoes violent change without detonating.

A waste meeting this characteristic would normally be in an unstable state; defined in general chemistry as compounds that readilydecompose or change into other compounds.  And it also must readily undergo a violent change without detonating (aka exploding).    Note that the trigger for the “violent change”, e.g. pressure, water, heat, &etc. is not specified.  It is clear that they do not mean to include explosives here as they are addressed later in this characterization.

A lithium battery may be a reactive hazardous waste due to its instability (Faxback 11274) unless it has been fully discharged (RO 11229).

I’m no scientist but here’s a good explanation of why lithium batteries sometimes go off:  Here’s why Lithium Batteries Occasionally Catch Fire.

Here is an example of a lithium battery’s instability:

Lithium batteries may be managed with other hazardous waste batteries as a universal waste.

Water Reactives:

It reacts violently with water.

It forms potentially explosive mixtures with water.

When mixed with water, it generates toxic gases, vapors or fumes in a quantity sufficient to present a danger to human health or the environment.

A waste that performs any one of the above actions when exposed to water must be assigned the characteristic of Reactivity.  Certain elements and substances, e.g. sodium and sodium azide, respectively are known to be water reactive and may be a reactive hazardous waste.  But note the use of subjective and undefined terms such as “violently” and “potentially explosive”.  Also, while the generation of toxic gases, vapors or fumes can be detected or known what can’t be determined from this characterization is what quantity is “sufficient to present a danger to human health or the environment”?  One possible tool for answering this question is to refer to the applicable worker exposure standards of the Occupational Health and Safety Administration (OSHA) for the gas, vapor, or fume generated.  If it is at or near the OSHA maximum exposure limit it may be sufficient to present a danger to human health or the environment(RO14636) (RO12249).

Cyanide or Sulfide Bearing:

It is a cyanide or sulfide bearing waste which, when exposed to pH conditions between 2 and 12.5, can generate toxic gases, vapors or fumes in a quantity sufficient to present a danger to human health or the environment.

To be a reactive hazardous waste due to this characteristic the waste must:

• Contain either cyanide or sulfide (an inorganic anion of sulfur).  The quantity or concentration is not specified.

And…

• When exposed to pH conditions between 2 and 12.5 – note that this pH range is not characteristic of a D002 corrosive hazardous wastewhich is a liquid with a pH of less than or equal to 2 or equal to or greater than 12.5. – generate dangerous levels of toxic gases, vapors, or fumes.

How can a generator determine a “quantity sufficient to present a danger to human health or the environment.”?

Well, in 1985 EPA provided interim guidance on determining these levels (Faxback 11091).  However, this guidance was withdrawn in 1998 and has not been replaced (Faxback 14177).  So it looks like you’re on your own.

Explosives:

It is capable of detonation or explosive reaction if it is subjected to a strong initiating source or if heated under confinement.

It is readily capable of detonation or explosive decomposition or reaction at standard temperature and pressure.

It is a forbidden explosive as defined in 49 CFR 173.54, or is a Division 1.1, 1.2 or 1.3 explosive as defined in 49 CFR 173.50 and 173.53.

Note the three separate definitions of an explosive.

1.  IT COULD EXPLODE IF TRIGGERED…

The first is merely “capable” of detonation (an explosion at faster than the speed of sound) or explosive reaction which is not quite the same as an explosion.  Further, the waste will only begin detonation or explosive reaction if it is subjected to a strong initiating force or heated under confinement.

So then, what about aerosol cans and other compressed gas cylinders?  Could they be a D003 reactive hazardous waste solely because of their capability of detonation or explosive reaction when heated or otherwise punctured?  The answer from EPA, surprising to me, was “maybe”.  In 1987 EPA stated that a discarded aerosol can is a reactive hazardous waste due solely to the propellent and not any other waste it contains (RO13027).  However, six years later in 1993 EPA refused to answer the question: “At this time, the Agency is not able to determine whether various types of cans that may have contained a wide range of products are reactive.”  The Agency went on to state that nearly empty steel aerosol cans are subject to the scrap metal exemption at 40 CFR 261.1(c)(6) and as such may even be punctured and drained without a permit (RO11782).

You may manage your hazardous waste aerosol cans under the scrap metal exemption.

My interpretation is that unless RCRA Empty, an aerosol can will – at a minimum – be a D003 reactive hazardous waste due to the contents or the propellant being under pressure and capable of detonation if exposed to…

a strong initiating source:

Or heated under confinement:

But as the generator you must determine for yourself if your non-empty aerosol cans display the characteristic of Reactivity.

Some states, such as California and Minnesota, allow non-empty aerosol cans to be managed as a universal waste.

But I may be wrong because even though EPA has refused to directly answer if aerosol cans are a reactive hazardous waste, it has stated that ammunition up to and including 0.50 caliber does not display the characteristic of Reactivity (RO 13712).  So, if ammunition is not a reactive hazardous waste due to its explosive nature perhaps aerosol cans aren’t either.

We have two more types of explosives to consider…

2.  MORE LIKELY TO EXPLODE WITHOUT A TRIGGER…

Another explosive characteristic is one that is “readily capable” of exploding at standard temperature and pressure.  Note that this is a much more reactive material since it is “readily capable” instead of just merely “capable” and it does not require heat or a strong initiating source.

3.  FORBIDDEN AND THE BIG BOOMERS…

And finally, it is a specified type of explosive as defined by the Hazardous Material Regulations of the USDOT/PHMSA.  So let’s take a look at them:

• Explosives that are forbidden in transportation by USDOT/PHMSA are identified at 49 CFR 173.54.  They include but are not limited to nitroglycerin, loaded firearms and toy torpedoes.  Simply refer to this
• 49 CFR 173.50 identifies the six different divisions of hazard class 1 Explosives regulated by the HMR.  The three divisions that will be a reactive hazardous waste upon disposal are the most dangerous:

(1) Division 1.1 consists of explosives that have a mass explosion hazard. A mass explosion is one which affects almost the entire load instantaneously.

(2) Division 1.2 consists of explosives that have a projection hazard but not a mass explosion hazard.

(3) Division 1.3 consists of explosives that have a fire hazard and either a minor blast hazard or a minor projection hazard or both, but not a mass explosion hazard.

Most consumer fireworks are a Division 1.4 Explosive and therefore would not display the characteristic of Reactivity when discarded.

Note:  A consumer firework that is a Division 1.4 Explosive may not display the characteristic of Reactivity but it may be a hazardous waste due to other characteristics such as Toxicity.

Commercial fireworks (the kind you see at a big show) and military munitions will likely be classified as a Division 1.1, 1.2, or 1.3 and will therefore be a reactive hazardous waste if discarded unused.

49 CFR 173.53 does not identify any new explosives not already identified in §173.50.  Instead it cross-references the current classification system of hazard class and division with a format used by USDOT/PHMSA prior to January 1, 1991 and still used by some states or other regulatory agencies.  Example:

• Division 1.1 = Class A explosives
• Division 1.2 = Class A or Class B explosives
• Division 1.3 = Class B Explosives
• Division 1.4 = Class C explosives
• Division 1.5 = Blasting agents
• Division 1.6 = No applicable hazard class

If you’re looking for clear-cut thresholds or approved analytical methods for the determination of the characteristic of Reactivity, you won’t find it here.  The determination of a reactive hazardous waste relies heavily on your knowledge of the process generating and the waste itself at the point of generation.