G.R. No. 84415 June 29, 1989
DIONISIA C. SANTE, in representation of her deceased husband SEVERINO T. SANTE, petitioner, vs. EMPLOYEES’ COMPENSATION COMMISSION, respondent.

FACTS

Severino T. Sante, a driver for the Ministry of Public Works and Highways, was diagnosed with amyotrophic lateral sclerosis (ALS) in 1981. His condition, involving progressive muscle weakening and difficulty in breathing and swallowing, forced his retirement. He filed a claim for disability benefits under P.D. No. 626, but the GSIS denied it, ruling ALS was not a listed occupational disease for a driver and that Sante failed to prove his work conditions increased the risk of contracting it. The ECC affirmed this denial. Sante died in 1984, and his widow, Dionisia, continued the claim. She invoked the Supreme Court’s ruling in Mercado, Jr. v. ECC, which held that when a disease’s cause is medically unknown, the claimant need not prove work-connection. The GSIS and ECC maintained their position, leading Dionisia to file this Petition for Certiorari instead of submitting additional evidence to the GSIS as directed.

ISSUE

Whether the petitioner is required to prove that her late husband’s illness, amyotrophic lateral sclerosis, was caused or aggravated by his working conditions as a driver, notwithstanding that the cause of ALS is unknown to medical science.

RULING

Yes, the petitioner has the duty to establish work-connection. The Court denied the petition, affirming the ECC’s order. The legal logic is anchored on the explicit provisions of P.D. No. 626, as amended, which established a state insurance fund with a no-fault and contractual liability system. Under this regime, for a sickness and resulting disability or death to be compensable, the law requires that the illness must be either: (1) listed as an occupational disease by the ECC, or (2) if not listed, proof must be shown that the risk of contracting it was increased by the claimant’s working conditions. ALS is not a listed occupational disease. Therefore, the claimant bears the burden of proving, by substantial evidence, a causal link between the employment conditions and the illness or an aggravation of the risk. The Court expressly overruled its previous decisions in Mercado, Jr. and Nemaria, which had dispensed with the need for such proof when a disease’s etiology was unknown. The Court in Raro v. ECC clarified that this earlier jurisprudence had improperly shifted the burden of proof and expanded liability beyond the statutory framework, effectively amending the law through judicial fiat. The law demands proof of work-connection, and the impossibility of pinpointing a medical cause does not relieve the claimant of this statutory obligation. However, the Court noted that proof need not be direct or scientific certainty; reasonable basis from real and substantial evidence suffices. The denial was without prejudice, allowing petitioner another opportunity to present such evidence before the GSIS.