When my husband and I bought our house in Concord 40-plus years ago, we were warned by the previous owners, “Don’t hang clothes out to dry because they’ll smell like gasoline from the refineries.” Refinery emissions, including the noxious odors, are no longer so obvious, but they still contribute to regional air pollution and global climate change.

Refineries process crude oil into gasoline, diesel, and aviation fuel, as well as lubricants and other products used in the petrochemical industry. As they do so, they emit many types of air pollution, including criteria pollutants, toxic air contaminants, and greenhouse gases. Refineries produce approximately 17 percent of the greenhouse gases in the Bay Area. They are the largest individual stationary sources of reactive organic gases, which react with nitrogen oxides to form smog, and they are also the predominant source of sulfur dioxide emissions in the region. Both sulfur dioxide and nitrogen oxides contribute to the formation of fine particulate matter, a significant health hazard.

Most people think of refineries as a collection of process units, pipes, and flares; they also include equipment like boilers, turbines, and heat exchangers. In addition to the air pollution generated by these systems, subsidiary facilities (like sulfuric acid plants) and activities like truck and tanker transport can also produce emissions. All of these sources are currently subject to some level of regulation by the Bay Area Air Quality Management District.

“We’re always looking for ways to reduce emissions from our largest sources of pollutants — checking opportunities by evaluating the cost-effectiveness of a measure,” said the agency’s Rule Development Manager Greg Nudd. The Air District is moving forward on a four-step plan to address refinery pollution: reduce harmful emissions; engage in continuous monitoring; limit pollution and protect health; and ensure refineries use best practices.

Step 1, reducing harmful emissions, is being implemented through the new “Petroleum Refinery Emission Reduction Strategy.” In December 2014, the agency’s board of directors set two targets for the strategy: a 20 percent reduction by 2020 in criteria pollutants and smog precursors, and also a 20 percent reduction in health risks from air toxics. Target pollutants include particulate matter as well as reactive organic gases, nitrogen oxides, sulfur dioxide, and ammonia.

The strategy has been broken into two parts, based on issues of timing. “Some things could be done quickly to lock in the benefits of emission reductions,” Nudd explained.

The first part of the strategy is a package of four new or amended rules which will be voted on by the Air District board in mid-December. The affected facilities include five refineries — Chevron, Shell, Phillips 66, Tesoro, and Valero — and five related facilities which serve the refineries. Based on emissions inventories from 2013-2014, the proposed package of rules is expected to reduce refinery emissions by 16 percent — 2,596 tons per year — by the target date of 2020.

A second package of rules will be presented in mid-2016 to achieve the rest of the 20 percent target. These rules can’t move as quickly through the process because the Air District staff still needs to gather relevant data. As Nudd put it, “For example, a gas-fired turbine at Valero might be cost-effectively controlled for nitrogen oxides, but what about the others that might come under the rule? They might need expensive environmental reviews or other measures.”

Step 2, continuous monitoring, and Step 3, the commitment to limit pollution and protect health, are being addressed by new draft rules — Rule 12-15 and Rule 12-16 — which will also go before the Air District board for a vote in mid-December. Rule 12-15 would improve the tracking of pollution from refineries, using state of the art methods that allow continuous updating. This would be combined with extensive air monitoring to verify that the reports are accurate and communities are not being subjected to unhealthy levels of pollution. Other reports would be required on facility energy efficiency and the types and characteristics of crude oil being processed. Health risk assessments, updated annually with the new emissions data, would be done on toxic air pollutants from refineries, using methods that emphasize protection for neighboring residents.

Rule 12-16 would set lower risk thresholds for refinery toxics, and place limits on certain pollutants to minimize health impacts on surrounding communities. It would also require refinery emission reduction plans, detailing how refineries not meeting the new limits can achieve compliance.

Changes to permitting regulations, to ensure best practices, will be Step 4. Refineries will be required to use the best available control technologies to ensure emissions don’t increase when modernizing facilities or changing the types of crude oil they process.

Environmental organizations are both pleased and disappointed by the proposed rules. “We are glad they are promising the frontline communities that have already suffered so much damage from the five refineries that they will reduce various pollutants and cancer risks from them by 20 percent over several years,” Jed Holtzman of the global nonprofit group 350.org commented by e-mail about rules 12-15 and 12-16, “but they are leaving greenhouse gases out of the rule.” He continued, “Protecting public health and the global climate is in the mission statement of the agency. Reducing [greenhouse gases] from refineries — both for their own sake and as a proxy for egregious co-pollutants impacting fenceline communities — is an extremely effective way to achieve this goal.”

Taking a different tack, the Western States Petroleum Association has objected to the rules because they would burden refineries in lieu of addressing larger sources of pollution. As WSPA pointed out in official comments submitted to the Air District this summer, the agency “identified that the most significant toxics impacts are not in the vicinity of the refineries, but are instead in the vicinity of ‘the maze’ of highways across from the Bay Bridge.”

Nudd agreed that refinery emissions are only part of the air pollution picture. “If you look at gasoline and diesel emissions, as well as emissions from refineries, that’s over 50 percent of the greenhouse gases in the Bay Area,” he said, adding, “Buying less gas is the real key to bringing down pollution.”

In any case, Air District data indicate that some critical components of air pollution in the region would be reduced by the proposed measures. The rules which the agency’s board will consider in December are the product of a two-year process and already include many changes made in response to industry challenges and pressure from environmental groups. However, they are not yet final. The only certainty is that refinery emissions will continue to be an issue of concern for everyone involved.

Leslie Stewart covers air quality and energy for the Monitor.