A group of representatives from various AFL-CIO unions urged passersby in the Boston Common last week to support the four-month-old Oil Chemical and Atomic Workers (OCAW) strike against Shell Oil Company.

Competing with an Earth Day Rally at the other side of the Common, union spokesmen described what they called the "hazardous safety conditions in Shell refineries which cause air pollution and "rainbow lung"--a lung disorder caused by chemicals that affects workers in the refineries.

At the same time, legislators across the street in the State House were debating a state proposal to improve industrial safety conditions and regulate health hazards in all industrial plants.

Spokesmen from the Boston Area Shell Boycott Committee, who organized the rally, said that they hoped to convince the legislature not to by-step the 1970 Federal Industrial Safety and Health Act in favor of a state law.

Kathy Stone, chairman of the committee, said that the state law would probably be less rigorous than the Federal one.

The OCAW strike erupted last January when Shell rejected the union's proposed health and safety program--a program which would establish a safety committee composed of refinery workers and managers.

The union is also urging people to boycott the Gulf Oil Company, from which Shell buys most of its crude oil.