[p. 811] ABRAMS, Justice.

 Pursuant to G.L. c. 278, ss 33A-33G, the defendant Ronald Rhoades, Jr., appeals three convictions of murder in the second degree on three indictments which charged murder in the first degree, a fourth conviction of murder in the second degree on an indictment which charged second degree murder, and a conviction of arson. . . .

 . . . . We accept . . . Rhoades' argument that the charge to the jury regarding the fourth murder indictment failed to describe adequately the causal connection which must exist between a defendant's act and a person's death in order for the Commonwealth to obtain a conviction on the theory of felony murder.  We therefore [p. 812] reverse this conviction.  . . .

 We summarize the evidence.  Santos Velasquez Murillo (Velasquez) and his family occupied the first floor apartment at 174 Pearl Street, Chelsea.  The apartment was located in a three story complex with three apartments on each side.  The building was numbered 172-174 Pearl Street.

 On December 31, 1977, Velasquez was at home taking care of his infant daughter.  Between 9 and 9:30 P.M., Rhoades arrived at Velasquez's apartment. Rhoades was not expected and had not been invited to the apartment. Approximately three weeks earlier, however, Rhoades had stayed overnight at the Velasquez apartment.  Velasquez showed Rhoades into his living room and offered the defendant a beer.  The men sat together in the living room; however, since Rhoades spoke no Spanish and Velasquez only very little English, there was little or no conversation between them.  Rhoades drank two or three beers.

 At approximately 10:30 P.M., Vasquez, a friend of Velasquez, arrived at the apartment.  Velasquez and Vasquez had some conversation in Spanish but neither one conversed [p. 813] with Rhoades.  At 10:55 P.M. Rhoades stated that he was going to the bathroom and asked for a cigarette.  He took one, the first he had smoked that evening, from Velasquez's pack on the coffee table and lit it with Velasquez's lighter.  The cigarette was the only thing in the defendant's hand as he left for the bathroom.  Neither Velasquez nor Vasquez saw Rhoades again that evening.

 The bathroom in the Velasquez apartment was located near the front door to the apartment.  Rhoades knew where it was, due to his visit to the apartment three weeks earlier.  On a shelf on the wall opposite, rather than next to, the toilet, stood a bottle of rubbing alcohol approximately six inches high and one-half to three-quarters full.  The bottle had been in the bathroom at the time of Rhoades' visit three weeks earlier.  When last seen on the night of the fire, the bottle, which was plastic, was capped.  Finally, on the linoleum floor of the bathroom, were some dirty clothes and a plastic tub of diapers.

 Approximately five minutes after the defendant left the living room, Vasquez smelled smoke, and Velasquez then saw flames.  The smoke and fire prevented them from leaving by the front doorway.  Vasquez therefore broke a window in the baby's bedroom and escaped.  Velasquez woke his sleeping child, handed her out the window to his friend, and climbed out himself.

 Shortly before the fire broke out, Paul Capozzi was standing on the steps outside the entrance way to number 172, waiting for his mother to return home to her second floor apartment on the number 172 side of the building.  Capozzi saw the defendant come out of number 174 and turn right onto Pearl Street, walking at a "little faster" than normal pace.  Rhoades passed within an arm's length of Capozzi, and proceeded to the corner of the block.  After disappearing from sight for approximately one minute, Rhoades reappeared, walking back up Pearl Street, to a position in front of a garage, directly across from number 172-174.  The defendant paused briefly, before proceeding at a normal or slightly slower than normal pace down the street to the opposite [p. 814] corner of the block, finally returning to stand across the street in front of the garage once again.  At this point, Capozzi, diverted by the fire which had broken out at number 174, lost track of the defendant's movements.

 Walter Juskiewicz was babysitting for three children, Michael and Dennis Elliot (ages 3 and 4) and Shawn Marceau (4 months), in the second floor apartment directly above the Velasquez residence.  Shortly after 11 P.M., Cathy Capozzi was outside 173 Pearl Street, across the street from her mother's apartment.  She saw Walter Juskiewicz come to the second floor window at number 174, yelling for help.  He dropped the baby Shawn to persons below, and disappeared from view.  During the course of the fire, Juskiewicz and the two Elliot children perished due to asphyxia caused by smoke inhalation.

 The first alarm for the three alarm blaze was sounded at 11:03 P.M.  Among the firefighters responding to the second alarm was Captain James Trainor.  When Trainor entered the burning building in an attempt to rescue persons thought to be trapped inside, he was outfitted in standard firefighting gear: rubber coat, helmet, boots and a self-contained breathing apparatus.  The temperature outside was in the 20's.  Attempting to assist those fighting the fire, Trainor encountered intense heat and thick smoke, and experienced difficulty in getting air through his face mask.  While on the roof of the building, Trainor collapsed; taken to a hospital in Everett, he was pronounced dead on arrival. The Commonwealth's medical expert concluded that the combination of cold weather, stress, and smoke inhalation precipitated the coronary thrombosis which caused Trainor's death.

 On January 3, 1978, two Chelsea police detectives and a member of the State police, all in civilian clothes, went to Rhoades' residence to question him concerning the fire at 172-174 Pearl Street and to arrest him on a warrant charging Rhoades with non-support.  Shortly after two of the officers appeared at Rhoades' third floor apartment and spoke to Rhoades' wife, the defendant walked out of a ground [p. 815] floor rear door being watched by the third officer.  When this officer identified himself, Rhoades, who was separated from the detective by a five foot fence, began running away.  Rhoades was arrested at gun point.

 Experts concluded that the fire was set.  Further they found that the fire began in the bathroom of the Velasquez apartment, that an accelerant was used to start the fire (presumably the rubbing alcohol), that the accelerant had to be ignited by an open flame, and that an accidently dropped cigarette was insufficient to ignite the accelerant or to start the fire.

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 The trial judge charged the jury that if Captain Trainor died "as a result" of Rhoades' act, or if Rhoades' act "in any way contributed to hasten, or was part of the proximate cause" of Trainor's death, then Rhoades could be liable for second degree murder.[n. 12]  The [p. 824] judge charged that if the jury found beyond a reasonable doubt, that Rhoades' act was a "contributing cause" of Trainor's death, then Rhoades would be criminally liable.  The overall effect of this charge was to leave the jury with the impression that if Rhoades' act in setting the fire in any way constituted a link, no matter how remote, in the chain of events leading to Trainor's death, Rhoades should be convicted.  We conclude that this formulation exposed Rhoades to potential liability for events not proximately caused by his felonious act in setting the fire.[n. 13]  See State v. Newman, 162 Mont. 450, 461-462, 513 P.2d 258, 265 (1973) (charge that the jury must find that defendant's act "contributed to or was the proximate cause of" the victim's death held to misstate the law because disjunctively phrased).  See generally, R. Perkins, Criminal Law, 685-738 (2d ed. 1969).[n. 14]
 

12. A reading of the record indicates that at trial it was the defendant's theory that the Commonwealth was required to prove that the fire was the sole or exclusive cause of Captain Trainor's death.  The defendant claimed an exception to "the Court's explanation that it's not necessary for the Commonwealth to prove that it (the fire) was the exclusive and sole reason for death, but was a contributing cause."  It would have been incorrect for the judge to have instructed the jury that the fire must be the exclusive and sole reason for death. . . .

13. A finding that Rhoades' conduct was the proximate cause of Trainor's death is an inference that a jury could well have drawn from the evidence in this case.  On appeal, Rhoades does not contend otherwise.  The Commonwealth's medical expert found that Trainor's efforts in fighting the fire "precipitated" the thrombosis that caused his death.  The defendant's expert testified that the stress of fighting the fire "contributed to" Trainor's "final thrombosis."  Nevertheless, a defendant is entitled to have the law correctly explained to the jury.

14. On this appeal, the defendant does not contest the premise that a person, found to have set a fire in circumstances constituting arson, may be convicted of murder or manslaughter if a firefighter dies in the performance of his duties.  See State v. Glover, 330 Mo. 709, 50 S.W.2d 1049 (1932).  Rather he claims that the jury should have been clearly instructed that the arsonist's act must constitute not just a cause, but also the proximate cause of the firefighter's death.

 [p. 825] This misimpression is not corrected by the impact of the instructions evaluated as a whole.  Commonwealth v. Burke, 382 N.E.2d 192 (1978).  Nothing said to the jury by the judge indicated that proximate cause in Captain Trainor's death "is a cause, which, in the natural and continuous sequence, produces the death, and without which the death would not have occurred."  California Jury Instructions, Criminal s 8.55 (4th rev. ed. 1979).

 The judge, apparently responding to the defendant's theory that he was criminally responsible only if he were the sole cause, merely attempted to instruct the jury that if Rhoades' conduct contributed to Trainor's death, Rhoades could be convicted.  See California Jury Instructions, Criminal s 8.58 (4th rev. ed. 1979).  He emphasized that the fire need not be the sole cause, but failed to instruct the jury clearly that the defendant's conduct must be the efficient cause, the cause that necessarily sets in operation the factors which caused the death.  The judgment on the indictment charging Rhoades with the death of Captain Trainor is therefore reversed, the verdict set aside, and the case remanded to the Superior Court for further proceedings consistent with this opinion.

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 So ordered.