Mine Safety Appliances Company (MSA)

Registrant’s telephone number, including area code: (412) 967-3000

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months and (2) has been subject to such filing requirements for the past 90 days.    Yes  x    No  ¨

Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Web site, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files).    Yes  ¨    No  ¨

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See the definitions of “large accelerated filer,” “accelerated filer” and “smaller reporting company” in Rule 12b-2 of the Exchange Act. (Check one):

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Act).    Yes  ¨    No  x

On April 30, 2009 there were 35,938,703 shares of common stock outstanding, not including 2,220,084 shares held by the Mine Safety Appliances Company Stock Compensation Trust.

Registrant’s telephone number, including area code: (412) 967-3000

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months and (2) has been subject to such filing requirements for the past 90 days.    Yes  x    No  ¨

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See the definitions of “large accelerated filer,” “accelerated filer” and “smaller reporting company” in Rule 12b-2 of the Exchange Act. (Check one):

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Act).    Yes  ¨    No  x

On October 24, 2008, there were 35,786,621 shares of common stock outstanding, not including 2,378,462 shares held by the Mine Safety Appliances Company Stock Compensation Trust.

Registrant’s telephone number, including area code: (412) 967-3000

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months and (2) has been subject to such filing requirements for the past 90 days.    Yes  x    No  ¨

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See the definitions of “large accelerated filer,” “accelerated filer” and “smaller reporting company” in Rule 12b-2 of the Exchange Act. (Check one):

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Act).    Yes  ¨    No  x

On July 25, 2008, there were 35,782,366 shares of common stock outstanding, not including 2,386,889 shares held by the Mine Safety Appliances Company Stock Compensation Trust.

Registrant’s telephone number, including area code: (412) 967-3000

Check the appropriate box below if the Form 8-K is intended to satisfy the filing obligation of the registrant under any of the following provisions (See General Instruction A.2):

Registrant’s telephone number, including area code: (412) 967-3000

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months and (2) has been subject to such filing requirements for the past 90 days.    Yes  x    No  ¨

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See the definitions of “large accelerated filer,” “accelerated filer” and “smaller reporting company” in Rule 12b-2 of the Exchange Act. (Check one):

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Act).    Yes  ¨    No  x

At April 30, 2008, there were 35,723,211 shares of common stock outstanding, not including 2,459,051 shares held by the Mine Safety Appliances Company Stock Compensation Trust.

Registrant’s telephone number, including area code: (412) 967-3000

Check the appropriate box below if the Form 8-K is intended to satisfy the filing obligation of the registrant under any of the following provisions (See General Instruction A.2):

On February 28, 2008, the Board of Directors of the Company amended the Bylaws of the Company, principally to permit the Chairman of the Board of the Company to be a person other than an executive officer of the Company. Under the Bylaws as they existed prior to the amendment, the Chairman of the Board was required to be an executive officer of the Company. Certain changes were made in Article III, entitled “Officers and Employees”, and in other sections of the Bylaws to effectuate this amendment. The powers and duties which had previously been exercised under the Bylaws by the Chairman of the Board are now assigned to the President.

In addition, Section 2.01(d) of the Bylaws was amended to provide that if a vacancy in the Board of Directors is filled by the majority vote of the disinterested directors, then any director that is so elected will be required to stand for re-election at the next succeeding annual meeting of shareholders. A copy of the Company’s amended Bylaws is filed herewith as Exhibit 3.1.

On February 28, 2008, the Board of Directors of the Company made certain changes to the Code of Business Conduct and Ethics of the Company. The principal changes to the Code were to clarify and reinforce the Company’s policy concerning the “appearance of impropriety” on the part of employees regarding ethical violations. Section A.7 of the Code, “Appearance of Impropriety,” was changed to require employees to seek approval from appropriate persons at the Company if a contemplated action might create the appearance of impropriety. In addition, language was added to that section and to Section B.1 of the Code, “Freedom from Constraints”, to clarify that employees must not engage in activities or transactions with the Company or otherwise that would improperly benefit the employee’s self interest (financial or otherwise) when the activity may be detrimental to the Company.

In addition, a new Section B.10 to the Code, “Insider Trading,” was added to apply along with the Company’s insider trading policy to all employees to prohibit trading in Company securities while in possession of material inside information and the “tipping” of others to such information.

(c) Exhibits. The following exhibits are filed herewith:

Registrant’s telephone number, including area code: (412) 967-3000

Check the appropriate box below if the Form 8-K is intended to satisfy the filing obligation of the registrant under any of the following provisions (See General Instruction A.2):

Registrant’s telephone number, including area code: (412) 967-3000

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months and (2) has been subject to such filing requirements for the past 90 days.    Yes  x    No  ¨

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, or a non-accelerated filer (as defined in Rule 12b-2 of the Act).

Large accelerated filer  x    Accelerated filer  ¨    Non-accelerated filer  ¨

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Act).    Yes  ¨    No  x

There were 35,646,371 shares of common stock, not including 2,545,954 shares held by the Mine Safety Appliances Company Stock Compensation Trust, outstanding as of October 31, 2007.

Registrant’s telephone number, including area code: (412) 967-3000

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months and (2) has been subject to such filing requirements for the past 90 days.    Yes  x    No  ¨

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, or a non-accelerated filer (as defined in Rule 12b-2 of the Act).

Large accelerated filer  x    Accelerated filer  ¨    Non-accelerated filer  ¨

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Act).    Yes  ¨    No  x

There were 35,780,109 shares of common stock, not including 2,612,644 shares held by the Mine Safety Appliances Company Stock Compensation Trust, outstanding as of July 31, 2007.

Registrant’s telephone number, including area code: (412) 967-3000

Check the appropriate box below if the Form 8-K is intended to satisfy the filing obligation of the registrant under any of the following provisions (See General Instruction A.2):

On August 2, 2007, the Company announced the sale of 83 acres of land located in the Company’s Cranberry Woods campus. A copy of the Company’s press release is filed herewith as Exhibit 99.1.

(c) Exhibits. The following exhibit is filed herewith:

Registrant’s telephone number, including area code: (412) 967-3000

Check the appropriate box below if the Form 8-K is intended to satisfy the filing obligation of the registrant under any of the following provisions (See General Instruction A.2):

On May 21, 2007, the Company announced a number of organizational changes, including the promotion of a named executive officer, Roberto Cañizares, to the position of Executive Vice President of the Company and President of MSA International and the retirement effective June 1, 2007 of named executive officer James Baillie, a Vice President of the Company and the President of MSA Europe. A copy of the Company’s press release announcing the changes is filed herewith as an exhibit and incorporated herein by reference.

Additional information concerning the executive officers involved in the changes, including their ages and five-year employment histories, is contained under the caption “Executive Officers of the Registrant” in Part I of the Company’s Annual Report on Form 10-K for the year ended December 31, 2006 and is incorporated herein by reference. In connection with the changes, three named executive officers, Mr. Cañizares, William M. Lambert, the Company’s President and Chief Operating Officer, and Dennis L. Zeitler, the Company’s Vice President, Chief Financial Officer and Treasurer, each received stay bonuses in the form of grants under the Company’s 1998 Management Share Incentive Plan of 12,438 shares of restricted stock. The restricted stock will vest in three equal annual installments on June 1, 2011 through 2013.

(c) Exhibits. The following exhibit is filed herewith:

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Registrant’s telephone number, including area code:  (412) 967-3000

Check the appropriate box below if the Form 8-K is intended to satisfy the filing obligation of the registrant under any of the following provisions (See General Instruction A.2):

On May 10, 2007, the Board of Directors of the Company approved amendments to the Company’s Restated Articles of Incorporation and By-Laws. The amendments add a new Section V to Article 5^th of the Restated Articles and amend Sections 4.01 through 4.04 of Article IV of the By-Laws to provide for the issuance of uncertificated shares.

Although the Company has no immediate plans to issue uncertificated shares, the amendments were adopted to comply with the requirements effective January 1, 2008 of amended Section 501.00(B) of the New York Stock Exchange Listed Company Manual. The amendments to the By-Laws were effective upon approval by the Board. The amendment to Restated Articles, which does not require shareholder approval, will be effective upon filing with the Pennsylvania Department of State, which is expected to occur during the week of May 14, 2007. Copies of the Company’s Restated Articles and By-Laws as amended are filed herewith as Exhibits.

(c) Exhibits. The following exhibits are filed herewith:

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Registrant’s telephone number, including area code: 412/967-3000

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months and (2) has been subject to such filing requirements for the past 90 days.    Yes  x    No  ¨

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, or a non-accelerated filer (as defined in Rule 12b-2 of the Act).

Large accelerated filer  x    Accelerated filer  ¨    Non-accelerated filer  ¨

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Act).    Yes  ¨    No  x

There were 35,924,730 shares of common stock, not including 2,669,709 shares held by the Mine Safety Appliances Company Stock Compensation Trust, outstanding as of May 7, 2007.

Registrant’s telephone number, including area code:(412) 967-3000

Check the appropriate box below if the Form 8-K is intended to satisfy the filing obligation of the registrant under any of the following provisions (See General Instruction A.2):

On March 15, 2007, the Company announced the election by the Board of Directors of William M. Lambert as President and Chief Operating Officer. The Company’s press release announcing the election is filed as an exhibit to this Report.

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Registrant’s telephone number, including area code: (412) 967-3000

Check the appropriate box below if the Form 8-K is intended to satisfy the filing obligation of the registrant under any of the following provisions (See General Instruction A.2):

On February 6, 2007, the Company’s Board of Directors elected Robert A. Bruggeworth as a member of the Board of Directors. The Company’s press release announcing the election is filed as an exhibit to this Report.

(c) Exhibits. The following exhibit is filed herewith:

Registrant’s telephone number, including area code: (412) 967-3000

Check the appropriate box below if the Form 8-K is intended to satisfy the filing obligation of the registrant under any of the following provisions (See General Instruction A.2):

Registrant’s telephone number, including area code: (412) 967-3000

Check the appropriate box below if the Form 8-K is intended to satisfy the filing obligation of the registrant under any of the following provisions (See General Instruction A.2):

Registrant’s telephone number, including area code: (412) 967-3000

Check the appropriate box below if the Form 8-K is intended to satisfy the filing obligation of the registrant under any of the following provisions (See General Instruction A.2):

Registrant’s telephone number, including area code: (412) 967-3000

Check the appropriate box below if the Form 8-K is intended to satisfy the filing obligation of the registrant under any of the following provisions (See General Instruction A.2):