safety lamp

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A miner's lamp with a protective wire gauze surrounding the flame to prevent ignition of flammable gases.

from The Century Dictionary.

• noun In mining, a form of lamp intended for use in coal-mining, the object of the arrangement being to prevent the inflammable gas by which the miner is often surrounded from being set on fire, as would be the case were the flame not protected from contact with the gas.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A miner's lamp designed to avoid explosion by enclosing the flame in fine wire gauze.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun an oil lamp that will not ignite flammable gases (methane)