Laboratory Safety:Management of Reactive Chemicals
A number of relatively common chemicals and reagents can become
explosive when stored improperly for excessive periods of time.
The following policy provides a list of the most common
potentially reactive/explosive hazardous chemicals and provides
information on how to prevent explosive hazards.
1. Peroxide Forming Chemicals
A variety of chemicals can form highly explosive peroxide compounds as
impurities when exposed to air over a period of time. This problem is
most common in ethers, but also occurs in a variety of other organic
compounds as well as in some alkali metals and amides. As a result,
great care must be taken to prevent the formation of peroxides in these
Preventing the formation of peroxides is dependent on careful inventory
control of peroxide forming chemicals. Most peroxide forming chemicals
are sold commercially with inhibitors to prevent the formation of the
peroxides. These are effective until the container is first opened.
After a container is opened, the chemical comes in contact with air and
may begin to form peroxides. Therefore, there are two steps to prevent
the hazards of peroxide formation.
The first step in preventing the formation of peroxides is to date all
containers of peroxide forming chemicals with the date the container was
The second step is to dispose of the peroxide forming chemicals within
six months of the date the container was first opened. Manufacturers
often state warnings on their peroxide forming chemicals. In this case,
the chemicals should be dated and disposed of in accordance with
manufacturers recommendations if more restrictive that the six month
disposal limit set by EHS.
The following list is composed of potentially reactive/explosive
peroxide forming wastes:
Allyl ethyl ether
Allyl phenyl ether
Diethylene glycol diethyl ether
Diethylene glycol mono-o-butyl ether
Dimethyl isopropyl ether
Ethyl Methyl ether
Ethylene Glycol Dimethyl Ether
Ethylene Glycol Ethers
Methyl isobutyl ketone
Organic ethers >1 year old
2. Picric Acid and other Polynitroaromatic Compounds
Picric Acid is commonly used in labs and is relatively safe in the form
which it is sold. It is ordinarily sold with 10% water added for
stabilization. However, picric acid can become explosive when it is
allowed to dry out or when it forms certain metal salts. The following
steps should be taken to safely store picric acid:
STEP 1: Never allow picric acid to be stored in containers with metal
caps or come in contact with any metal.
STEP 2: Check Picric Acid frequently to ensure it remains damp. Add
water if needed.
STEP 3: Never attempt to open a bottle of old or very dry picric acid.
Contact EHS if this occurs.
Contact EHS for handling and storage information if other
polynitroaromatic compounds are used in your laboratory.
3. Tollen's Reagent
Tollen's Reagent (ammoniacal silver nitrate) can form highly explosive
silver fulminate over time after it has been used. To avoid this
problem, add dilute nitric acid to Tollen's Reagent immediately after
use and contact EHS for disposal.
4. Sodium Azide
Sodium Azide may form highly explosive heavy metal azides if
contaminated or used improperly. Disposal of sodium azide solutions to
the sanitary sewer may cause the formation of lead or copper azide in
the plumbing which could potentially cause a serious explosion. Sodium
Azide should never be heated rapidly or stored in containers with metal
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