Opinion by

This is an appeal from an award granting compensation for death resulting froni. anthraco-silicosis under the Occupational Disease Act of 1939. The referee denied compensation on the theory that..§ 301 (g) requires an exposure of six months or more to a silica hazard sub *179 sequent to tlie effective date of the Act,, and that the requisite ninety day notice to the employer had not been, given. The referee further concluded that the Eureka Casualty. Company .was.not liable as its policy. w,as terminated prior , to. the . employe’s disability or death, These three conclusion^ of law were vacated by the. board and compensation was allowed., The. court, below dismissed the appeal, by the employer and, the insurance carrier, entered judgment upon the.award, and from that judgment this appeal was taken. The Commonwealth, against which payment of one-half of the compensation was awarded, did not appeal. , .. i

■ Claimant’s husband was employed in, the anthracite coal mines from 1893 t,o January 22, 1941. in various capacities. From 1893; to August, 1936 he was employed by the Philadelphia and Reading Coal and Iron Company and from August 21,1939 until March 13,1940 by the Bergen Coal Company and from October 1, 1940 to January 22,1941 he was employed by the Pottsville Coal Company, He died January . 24, 1941. His widow filed her claim petition on December 1, 1941.

.Appellants raise four questions: (1) Was the employe’s death, due solely to silicosis? (2) Was there a sufficient period of exposure to .comply with § 301(g) of the Occupational Disease Act? .(3) Was there an exposure to a silica hazard during an aggregate, employment of four years for a period of eight years next preceding the date of death? (4) Was the action brought within the requisite period of time?. These questions will be, answered in the .affirmative, and the judgment will be affirmed. .

(1) The Occupational Disease Act of June 21, 1939, P. L. 566, as amended, § 301 (:e),.77.Pg .§1401, provides that compensation is only payable for total disability or death .caused solely (as distinguished from a contributory or accelerating cause ) by silicosis, anthraco-silieosis, or *180 a'sbestosis, either alone or accompanied by active pulmonary tuberculosis.

The board found the deceased became totálly disabled and died as the result of anthraco-silicosis. The attending physician testified: “The cause of death was given [in the certificate of death] as ‘coronary embolism, probably’. Mr. Holahan had anthraco-silicosis in an advanced stage. He died so suddenly when this occurred that tlie man was dead* when I arrived there. In my opinion the death was due to anthraco-silicosis which produced this embolism, whether coronary or pulmonary.” (Emphasis added.) In answer to a question by thé réferee, the doctor testified that anthraco-silicosis was the primary cause of death.

The deceased did not have to be entirely free of physical infirmities save the fatal silicosis in order for that disease to be the sole cause of death within the meaning of the Act. The' mere existence of Some independent physical weakness, as a passive factor in causing death, is insufficient to deprive the silicosis of its character as the sole producing cause which terminated the employe’s life. Treaster v. North American Refractories Co., 156 Pa. Superior Ct. 567, 41 A. 2d 53. The silicosis must be the active agency causing death as distinguished from a “passive ally”. If the silicosis only contributes to or accelerates death then by the express language of the Act it is not'compensable. Stauffer v. Hubley Mfg. Co., 151 Pa. Superior Ct. 322, 30 A. 2d 370.

Under the Occupational Disease Act the board is the ultimate fact finding body. Tokash v. Early Foundry Co., 157 Pa. Superior Ct. 467, 43 A. 2d 553; Jaloneck v. Jarecki Mfg. Co., 157 Pa. Superior Ct. 609, 43 A. 2d 430. Its findings will not'be disturbed Where, as here, they are supported by substantial competent evidence.

(2) Section 301 (g) of the Occupational Disease Act, supra, provides : “The employer liable for the compensation provided by this article shall be the employer in *181 whose employment the employe was last exposed to the hazard: of the occupational disease-claimed, regardless of the length of time of such,last exposure: Provided, That when a-claimant alleges that disability - or death was due to silicosis, anthraco-silicosis, asbestosis or any other occupational disease-which developed to .the .point of disablement-, only after an, exposure of five or more years, the only employer liable shall be the last employer in whose employment the employe was last exposed to the hazard of such occupational disease during a period of six months or more after the effective date of this act; and in such cases an exposure during a period of less than six months after the effective date of-this act shall not be deemed an exposure. The notice-of disability or death and claim shalbbe made to the employer who is liable under this subsection, and his insurance carrier, if any.” This-section pertains -to the liability of successive-employers. 1 -Appellants construe, this, section to mean that there must be an exposure for- at least six months from- and after October 1, 1939, the effective date of the act,- to render the employer liable. , The deceased was employed- ;by the - defendant for only five months thirteen days after the effective date, but he had been exposed to the occupational hazard with his last employer for six months and twenty-three days. ■

This section was before us in Silva v. Erie Forge Co., 149 Pa. Superior Ct. 251, 27 A. 2d 727, where, the claimant had been employed for thirteen years by the .same employer and was-totally disabled on December 12,1939, less than three months after the-effective date of .the Act. In allowing compensation we pointed out that § 301. (g) provides that the employer in whose'employ the employe was last exposed to the hazardous occupational disease *182 was liable regardless of the length of time of the exposure. But we stated that certain occupational diseases such as silicosis; anthraco-silicosis, asbestosis and other occupational diseases which required an exposure of five years or more were an exception under the Act. In the latter type of disease, after October 1, 1939, the exposure hád to be for six months or more. Therefore, after October 1, 1939, liability attaches to the last employer after ah exposure to a silica hazard for at least six months. But this does not mean that the six months must occur' subsequent to the effective date of the Act.

(3) Section 301 (d) of the Occupational Disease Act, supra, allows compensation for silicosis and anthracosilicosis only if there is an aggregate employment in this Commonwealth for at least four years during a period of eight years next preceding the date of disability; in an occupation having a silica hazard.

However, periods of exposure may be combined'to reach the requisite four years but not periods of employment where there was no exposure to a hazardous occupational disease even though the employer is the same. Tokash v. Early Foundry Co., supra; Bingaman v. Baldwin Locomotive Works, Inc., 159 Pa. Superior Ct. 29, 46 A. 2d 512.

The deceased was certainly exposed to a silica hazard since January 22, 1933 (eight years preceding the date of disability, January 22, 1941); for three years,'seven months and nine days while in the employ of the Philadelphia and Reading Coal and Iron Company; and for six months, twenty-three days while employed by the appellant. Thus there‘was aggregate-exposure-of moi’e than four years which meets the statutory requirement.

(4) Section 311 of the Occupational Disease Act, supra, provides that notice of disability must be given to the employer within-fourteen days after the disability begins and unless such notice is given within ninety days no compensation is allowed. The omission to give the *183 ninety day notice is fatal to a claim. Roschak v. Vulcan Iron Works, 157 Pa. Superior Ct. 227, 42 A. 2d 280. The statute of limitations, starts to run from» the date of total disability. Roschak v. Vulcan Iron Works, supra; Agostin v. Pittsburgh Steel Foundry Corp., 157 Pa. Superior Ct. 322, 43 A. 2d 604, affirmed 354 Pa. 543, 47 A. 2d 680.

While any claim, by the employe would be barred the question is what effect the failure to .give notice has on the rights, of the widow.. Under, the Workmen’s Compensation Act that right was held to be independent and not derivative. Rossi v. Hillman Coal & Coke Co., 145 Pa. Superior Ct. 108, 20 A. 2d 879; Polk v. Western Bedding Co., 145 Pa. Superior Ct. 142, 20 A. 2d 845; Lambing v. Consolidation Coal Co., 161 Pa. Superior Ct. 346, 54 A. 2d 291. The Occupational Disease Act is a supplement to the Workmen’s Compensation Act of 1915, as amended. Jones v. Philadelphia & Reading Coal & Iron Co., 154 Pa. Superior Ct. 465, 36 A. 2d 252. Both Acts provide that claims .for compensation shall be barred unless brought within one year; Claimant had merely an inchoate right to compensation until her husband’s death. At that time her right accrued^ afid; this action is not barred since she, filed her claim petition within one year.

The board properly held the Eureka Casualty Company liable on its policy. The deceased’s last exposure to a silica hazard was ofi March 13, 1940, and Eureka was the insurance carrier at that time. See Anderson v. Schroeder Monumental Works, 159 Pa. Superior. Ct. 620, 49 A. 2d 631; Gaydosh v. Richmond Radiator. Co., 164 Pa. Superior Ct. 154, 63 A. 2d 502.

Judgment affirmed.