Patent for a means for preventing the accumulation of gas in manholes, 1891. This device also helped prevent ice buildup that froze manhole covers in place. Patented by Charles W. Hays on August 11, 1891. U.S. Patent No. 457,436. See full text description. (Use back button to return to graphics section.)

Source: United States Patent and Trademark Office at http://www.uspto.gov.

Appliances used in the maintenance of sewers at Providence, Rhode Island, 1899. Notice sewer entry equipment in the upper right photo

Source: Engineering News and American Railway Journal, Volume XLI, No. 13 (30 March 1899) insert facing p. 200.

Sewer crew: Two men pull a coworker from an alley sewer manhole. Denver, Colorado. The man in the hole wears a mask, other men stand by. Dated between 1920 and 1940. Photographer: Harry Mellon Rhoads, 1880 or 81 - 1975.

Source: Western History/Geneology Department, Denver Public Library. All rights reserved.

This equipment was made by the Mine Safety Appliances Company (M-S-A) circa 1930. It was created to help facilitate safe entries into confined spaces such as sewer manholes. Air was supplied from a "steamer trunk" containing a fan. A hand-operated crank sent the air through the hose to the mask.

Source: Advertisement for Mine Safety Appliances.

Photograph of the type of equipment used in the MSA advertisement shown above.

Source: Collection of Jon C. Schladweiler, Tucson, Arizona.

Advertisement for rubberized protection suit and combination hose mask used for sewer entries, 1946. Air was forced through the hose to the mask by a co-worker using a hand-cranked air pump. Manufactured by the Mine Safety Appliances Company, Pittsburgh, PA.

Source: Sewage Works Journal, Volume XVIII, No. 2 (March 1946), p. 17 (in advertising supplement).